This is a Tekno RC 12mm Nylon M6 Driveshaft Hex Adapter Set. These 12mm hex adapters are intended for use with Tekno RC M6 6mm Driveshafts. They fit all 12mm hex SC wheels and have a 6mm inner bore to fit the M6 Stub Axles. These may be used on other 6mm axle applications.
This product is expected to arrive on Wednesday, January 16 2019