These are printed in-house in Tennessee using TPU, which means they are soft and slightly rubbery. TPU is what a lot of phone cases are made out of.
Due to the nature of 3D printing, especially with flexible materials, there will almost certainly be surface imperfections, but nothing to impact the functionality of the product. For now, the color will be random.
These are useful for keeping paired cells together. They offer a tiny amount of impact protection, but it is never a good idea to expose lithium-ion cells to impact.
Price is per 2x pieces, or enough to cap both ends of two cells. They fit both protected and unprotected cells.
I am not responsible for injury, death, your house burning down, thermonuclear war, or anything that could possibly occur as a result of using this product.