SK Hand Tools 384 3/8-Inch Female and 1/4-Inch Male Adapter 1/4-inch(F) to 3/8-inch(M) chrome adapter, made in the United States Patented SuperKrome finish for durability and maximum corrosion resistance Allows greater flexibility for all your sockets and drive tools; ball detent securely holds all sockets on the coupler Steel ball is spring-loaded for easy use Adapter measures .068 inches in diameter and 1.12 inches long