These ratchets and rings replicate the manual winches used on the side of a flatbed, tarp sided trailer or just about any semi truck trailer that uses strapping to hold down a load. There are 20 ratchets in each set, as well as 20 rings, that can be used two ways: Cut the sprue leaving a little on the back and drill the holes to match where you want to mount them, or two; sand the backs flush and mount using superglue or similar adhesive. They have passed the checks for the detail materials, but should there be a problem, contact me via the shapeways designer ink, or direct via email to modelmechanic@gmail.com