Asking for so many clues already?
Plastic, but they also come in rubber.
I've never seen one personally and no dimensions are given, but an uneducated guess would be around the size of a pack of smokes, maybe slightly larger.
Phinz; A toothbrush?!?! A toothbrush?!?! Since when did you get sneeky enough to put such a basic item up for guessing? That's like YT putting a knitting needle up!
Sheesh, you think you know a guy.......