Totally functional, had my watch band apart before the mailman even left my street! Considering this was about half of what the jeweler charges me to fit bands, and I'm addicted to buying watches on Amazon (I need help... or maybe a raise? lol)... 100% great purchase.
There are spare pins included. The material is painted and doesn't scratch the watch. The screw is nylon- not the best choice of material for commercial use since it will wear over time, but from a machining standpoint, it keeps costs WAY down by allowing looser tolerances on the thread cutting operation, and less tool wear on the lathe. Home users won't use it enough to ever wear it out. There's also a little table that screws up and down to set the pin height to match the thickness of the links. Thumbs up.