NIUNIU PACKAGE CONTAINS: 3Pcs:1/4" , 3/8", 1/2"each with a 1/4" hex shank/driver bits fits all quick-change drill chucks system,4 piece converter Set includes sizes 1/2-inch(F) x 3/8-inch(M), 3/8-inch(F) x 1/4-inch(M), 3/8-inch(F) x 1/2-inch(M), 1/4-inch(F) x 3/8-inch(M).Turns any power drill into a power nut driver Sturdy spring-loaded ball bearing holds sockets securely in place Sockets Snap-On Tightly and Won't Slip Off. General Usage: This 3 piece Hex Shank Bit Driver Extension Bar Set is designed and 4 piece converter se plated adapters to meet a variety of needs. Fits snugly and securely in your drill chuck or hand held driver. Consisting of your most common bit sizes 1/4", 3/8", and 1/3" changing shank sizes. Provides versatility and convenience no matter which tool you chose to use. Great for the DIY, household maintenance, and most general repairs, not for industrial work. DESIGN: The Shaft Quick Change Hex Design allows to switch easy fast between the different size adapters without stripping at high speed operations - Sandblasted Finish for best durability - Spring Loaded Extension Ball Bearings holds onto the sockets securely preventing fall-offs.Material:Chrome Vanadium Steel for home use - Specification: Sockets Standard 1/4" hex shank to 1/4" 3/8" 1/2" socket 1/4 " shank can be converted to 1/4" 3/8" 1/2" square head. Durability: Quality is a guarantee with this 3 piece and 4 piece sturdy and durable solid steel set designed to withstand torque compression under most standard use situations. The exterior anti-weathering coating provides extra protection from damage against elements and substances such as oil and fluids that may come in contact with the extension bars during use with repairs such as in the automotive field. Colour: Black Included in delivery: 7 pieces, post-sleeve adapter