Each texture has a name and a written description, but Fleshlight publishes no comparable measurements for it – neither canal diameter, number of chambers nor firmness. What you have to go on is the manufacturer's descriptions and, for some models, cross-section images on the packaging. Some examples of how the descriptions differ:
Riley Reid's three textures are ranked by the manufacturer itself: Insomnia is labelled “Highest Suction Effect” and “Top Rated Overall”, Euphoria “Tightest Feel” and Utopia “Most Intense”. Lana Rhoades Karma is described in four sections – wide sculpted pockets, compression rings, angled ridges and tapering chambers – while Destiny does the opposite and starts with rings. Elsa Jean Tasty is described as rounded chambers, a smoother central canal and a twisted finish.
Turbo Tech is a patented system with suspended entry rings that, according to the manufacturer, grip around the shaft, and it comes both in Full Size and as Quickshot Turbo. Stamina Training Unit has the Endurance texture with large nubs throughout the canal, rated as “tight” in the manufacturer's product data and marketed for stamina training.
The practical advice: don't choose a texture based on someone else's ranking. Within the Fleshlight Girls range the models share case, material and care, so choose by format and opening first – and then by the description that appeals to you.