Had seen these a while ago and always meant to try them so when I placed an order this week, I remembered to get a couple to try them out.
Fender doesn't say what the material is but their directions for care (don't flex, avoid heat, avoid moisture) combined with their statement they are made from an animal protein, make me think they are some variety of casein/galalith.
They make them in a few shapes and they come in as medium, heavy, or extra heavy. I ordered the 346 shape in extra heavy. Here's one beside a celluloid extra heavy in the 346 shape.
The Tru-Shells seem very slightly larger and marginally thicker than their celluloid counterparts.
In playing, first thing I noticed is that they are quite loud for a standard pick this thick. Very good volume. Tone was warmish if maybe a little on the dull side but perfectly acceptable. Control was excellent as you might expect from a pick this thick. The surface is very slightly textured and grip seemed fine.
In keeping with my theory that all picks come with "some assembly required", pulled out the files and buffers and went at it. Never seen the value of three identical points on a pick. Never wore one out or broke a tip in a situation where I needed two redundant back ups, so I figured more utility in having 3 different tips on hand. Here's the original and the modified version.
In addition to reshaping, I put a full edge chisel bevel on all three new points. I did notice while polishing the edge that it buffed out smooth as glass so the texture is superficial only for grip.
The changes resulted in it being even louder, shifted the tone to more neutral/cool, and enhanced the control slightly. One warning, if you decide to get one and modify it at all, do not try to use a power tool to do it. The material shapes very quickly with only light pressure using a fine grit nail shaping file. You have to be careful with this stuff even with the hand file so one tiny slip with a Dremel and its good-bye pick.
Overall, pretty impressed by the performance of these picks. They are not cheap but at $5.99 each they are in the lower cost bracket for specialty picks and a real bargain if they are , in fact, casein. Need to play them more, but, at this point, I'd be happy to use them anytime.