These quick change router chucks allow you to change router bits in 5-10 seconds with only one hand and a hex key wrench. Holds bits securely yet eliminates wrestling with wrenches, leaves one hand free to hold bit in the collet and lessens your chances of nicking or pinching fingers. Choose the version that fits your router. Chuck accepts 1/2" shank bits directly into collet, Use appropriate reducing sleeves for 1/4" shank bits.