Guide · Dildos
A dual density dildo is moulded in two layers: a firmer core that holds the shape and a softer outer layer that gives against the body. That lets the dildo feel soft without going floppy – but the material in both layers, the dimensions and the care still decide whether it suits you.
Density here roughly means firmness. A single density dildo is moulded from one material with the same firmness all the way through – it's either soft throughout or firm throughout. A dual density dildo has two layers: a stiffer core in the middle and a softer material on the outside. In Swedish it's called dubbel densitet, but dual density is the term that most often appears in the product name.
The point is to get two qualities that otherwise get in each other's way. A soft material feels pleasant but can bend too much, especially in a long dildo or in a harness. A firm material holds its shape but doesn't give at all. With dual density, the surface should feel soft while the core makes sure the dildo can be guided.
It isn't a mark of quality in itself. Dual density comes in both platinum silicone and TPE, and in the models we've reviewed no manufacturer publishes any measured value for how soft the outer layer or how firm the core actually is. So you still need to look at material, dimensions and care instructions – just as with any dildo.
The principle is the same for every manufacturer, but the solutions differ. Three examples from our reviews show the range.
Silexd builds its dildos with a core of SILEXPAN®, a patented material the manufacturer describes as a core with shape memory, under an outer skin of platinum silicone. The manufacturer states that the material is phthalate-free and non-porous. What the manufacturer doesn't publish is what the SILEXPAN core is made of, which we point out in the review of Silexd Silex-D 17.6 cm.
Pipedream builds King Cock Elite 20 cm with silicone in both layers: a soft outer skin over a stiff inner silicone core, according to the manufacturer's own cross-section image. It's one of the few examples where the manufacturer states the same material family all the way through.
ToyJoy uses TPE in Get Real Dual Density Dong 23 cm: a soft outer layer over a firmer core, and the manufacturer's construction graphic also shows a flexible channel through the core that ToyJoy calls Flexi Shaft. So the same principle, but in a porous material and with a different idea of how much the shaft should be able to bend.
The biggest difference shows in how the dildo behaves under pressure. A soft single density dildo gives along its entire length; it can feel nice but is harder to guide and can bend away when used in a harness or on a suction cup. A firm single density dildo – or a glass one – holds its shape completely but gives nothing back. Dual density tries to sit between the two extremes.
That doesn't mean single density is worse. Many fantasy dildos and most PVC dildos are moulded in a single material and work perfectly well. What matters is whether the firmness suits you, and that can be hard to judge in advance because manufacturers rarely publish it. Glass is the clearest example of a completely firm material; read more about it in are glass dildos safe?.
One more practical difference: since the outer layer is the only part that touches the body, it's the outer layer's material that determines lube, cleaning and how long the dildo lasts. If the outer layer is damaged – by the wrong lube, for example – the core ends up closer to the surface. The Silexd review covers exactly that risk.
The material of the outer layer is the most important choice. Silicone is non-porous: the surface is sealed, can be cleaned completely and copes well with soap and water. TPE is a thermoplastic elastomer that is soft and skin-like but porous, which means it can be cleaned on the surface but not sterilised. The full rundown is in body-safe sex toy materials.
The difference shows in the manufacturers' own instructions. For Silexd Silex-D The Original 26.6 cm Silexd states that the dildo can be sterilised by boiling for three minutes. For ToyJoy's TPE model, the manufacturer's user manual states that the product must not be exposed to temperatures above 45 degrees, which rules out both boiling and the dishwasher.
The documentation differs too. King Cock Elite is listed as silicone throughout but without an explicit phthalate declaration from the manufacturer. ToyJoy's dual density dong is listed only as TPE, with no phthalate declaration, firmness value or manufacturer warranty. Silexd declares it phthalate-free and non-porous but doesn't publish the composition of the core. None of them is complete, and that's worth knowing before you compare on price.
The TPE models are cheaper and can have unusual dimensions. ToyJoy's dual density dong has 20.75 centimetres of insertable length on a shaft only 4 centimetres in diameter according to the manufacturer's dimension drawing – a format that's hard to find in silicone. What you give up is sterilisation, a material declaration and the option of warming the dildo.
If you compare with a single density dildo in the same price range, such as King Cock 15 cm, it's made of PVC. The manufacturer doesn't state dual density there and publishes no firmness; one shop describes the stiffness as firm. PVC and TPE share the same limitation: they can be cleaned on the surface but not sterilised.
Silexd markets its dildos as thermoreactive: the material gets softer when warmed and firmer when cooled. It's a property the manufacturer describes itself, and for the 26.6-centimetre model Silexd also gives times – at most 30 seconds in a microwave and at most 2 minutes in water for warming, and the fridge for cooling.
No maximum material temperature in degrees is published. That means you have to check the result yourself: feel the dildo in several places before using it, as the heat can spread unevenly. For the smaller 17.6 cm model, the time limits come from shops and not from the manufacturer.
Thermoreactivity applies to Silexd. It can't be carried over to other brands: according to its user manual, ToyJoy's TPE model must not be warmed, frozen or exposed to temperatures above 45 degrees, and Pipedream generally advises against extreme temperatures for King Cock.
The hardness of soft materials is often measured in Shore A. That would be the most useful figure for anyone who wants to know how a dual density dildo feels – but none of the manufacturers in our reviews publishes it. Instead you get words like soft, medium, firm or supersoft, and they mean different things at different brands.
The problem isn't unique to dual density. Mythology describes its fantasy dildo Kuno Utopia both as stiffer than the rest of the range and as super soft, and Epic calls the material in Nixie both supersoft and fully flexible – with no measured value in either case. When shops state a firmness, it's their own assessment.
The practical advice is to read the description of the construction rather than the adjectives. If it says a firm core sits under a soft outer layer, you at least know how the dildo is built. If it just says soft or firm, you know less than it sounds.
A soft outer layer can make a dildo feel a little more forgiving, but the diameter is the same. Choose size by insertable length and diameter just as usual. Among the models above, the range runs from Silexd 17.6 cm with 13.6 centimetres insertable and 3.5 centimetres in diameter to King Cock Elite and Silexd 26.6 cm at 5.4 centimetres in diameter.
Also look at the difference between total length and insertable length. ToyJoy states 23.5 centimetres in total but 20.75 insertable – the rest is suction cup base. Silexd 17.6 cm has 13.6 centimetres insertable. How to read the dimensions, and what size usually works as a first dildo, is covered in what size dildo should you choose and 10 things to know about your first dildo.
Also be wary of shop dimensions. In the Silexd review, three out of seven shops give the wrong total length for the same item, and for the 26.6-centimetre model the manufacturer's box says 26.6 centimetres while the specification says 25. The manufacturer's dimension drawing is the safest source.
It's in a harness and on a suction cup that a firm core does most good, because the dildo then has to hold its shape without a hand guiding it. Silexd states that Silex-D fits most harnesses and stands, and Pipedream states that King Cock Elite works with most traditional harnesses and with the manufacturer's own Body Dock system.
Look at the ratio between weight and suction cup. Silexd 17.6 cm weighs 251 grams on a suction cup 6.7 centimetres wide. Silexd 26.6 cm has the same 6.7-centimetre suction cup but weighs 460 grams – something the review notes as a weakness. King Cock Elite has a 7.8-centimetre suction cup on 511 grams. More on surfaces and attachment in suction cup dildos.
For the harness you also need to know the base dimensions in relation to the O-ring. Pipedream doesn't publish the neck diameter for King Cock Elite, so compare the base and shaft dimensions with the ring before you buy. How O-rings and harnesses work is covered in how does a strap-on work.
Use water-based lube. That applies to every model in this guide: Silexd advises against both silicone- and oil-based lube on its silicone products, ToyJoy's user manual states that oil- and silicone-based lubes can damage the material, and Pipedream recommends water-based for King Cock. More on the choice in which lube to choose.
Clean before and after use with lukewarm water and mild, unscented soap, and let the dildo dry completely. Silexd specifies neutral soap without fragrance or alcohol and explicitly advises against the dishwasher. Pipedream specifies antibacterial cleaner and warm water and says the product should air-dry completely before storage.
Store the dildo so it isn't touching other toys. Silexd recommends a breathable fabric pouch and that silicone products are stored separately from one another. If you share the dildo, wash it between each person or use a new condom each time, and remember that oil weakens latex condoms. The full rundown is in how to clean sex toys.
Thinking dual density means silicone. The principle exists in TPE too, and then TPE's limitations on cleaning and temperature apply.
Using silicone lube. A damaged outer layer can't be repaired, and on a dual density dildo the outer layer is the only thing protecting the core.
Warming a dildo that isn't meant for it. Thermoreactive is a property of certain models – not of dual density in general.
Comparing on total length. The suction cup base counts towards the total length but not the insertable length.
Trusting adjectives like soft and firm. Without a published Shore value they're a description, not a measurement.
Dual density suits you if you want a realistic feel – a surface that gives but a shaft that holds its shape – and especially if you want to use the dildo in a harness or on a suction cup. It also suits anyone who finds completely firm materials like glass too hard but doesn't want a dildo that bends every which way.
If you want a dildo that can be boiled and cleaned completely, choose dual density in silicone and check that the manufacturer states it can be sterilised. If budget matters most, TPE can work, but expect that it can't be sterilised and should be used with a condom if shared. More realistic models, with and without dual density, can be found in best realistic dildos, in our guide to realistic dildos and under dildos. How we read manufacturers' information is described under how we review.
