1/4 Inch Shank Router Bit Collet Extension Chuck Converter Adapter, Convert 1/2-Inch & 1/4-Inch Shank Bits with ER20 Spring Collet, ER20 M Type Collet Chuck Wrench Spanner, Wrench(17MM)- Pack of 5 -
7 Pieces Set Impact Drill Socket Adapter, 1/4"3/8"1/2" Hex Shank Adapter Reducer with Extension Set Impact Driver Conversions, Active Rust Protection By Black-Phosphate Coating Treatment - Amazon.com
CURT Receiver Tube Adapter (2" to 1-1/4" Shank, 3,500 lbs. GTW, 4" Length) 45770 - The Home Depot
Whiteside - 6400 Router Bit Shank Reducer 1/2" to 1/4"