Grinders are usable things, used mostly for crushing herbs into smoking substances. We have acrylic grinders, metal grinders, wood grinders, many sizes from 1.6 into 3 in. Grinders shaped like a box or round ones. Metal grinders are most popular and durable, plastic or acrylic are cheap and wooden are made from natural material and feels good in hands. We also have grinders made from natural plastic – hemp plastic. This material is made from cannabis plants and used wisely to make such things as grinders.