The inserts in our duck calls are made from a hard bulletproof plastic resin known as, PolyCarbonate. All inserts are pre-tuned before leaving the shop, and come in the option of single or double reeds. Double reeds are easier for new callers to blow while single reeds are more versatile with what you can do with them, but are suggested for the seasoned caller. The available colors include Black, Bourbon, Clear, and Smoke.