I originally designed the first Mecanum wheel adapters to attach VEX Mecanum wheels to my robot for the FIRST Tech Challenge. Today, there are a few versions, and this particular one follows the evolution of the competition as teams move away from tetrix parts toward other kits of parts. These adapters are for attaching .77" profiles (such as actobotics frames from ServoCity.com) to VEX Mecanum Wheels. Keep in mind that you will need two sets of these to use 4 Mecanum Wheels. I also recommend buying
mounting backs, which are also sold on my shop.
VEX Mecanum Wheels