These are the ST Racing Concepts CNC Machined Aluminum Hex Adapters|
For the Traxxas Slash 4x4 1/10 truck
The 12mm Machined Hex adapter securely mounts on your Slash 4x4
tires and wheels with no chance of it being rounded off under heavy
torque and power loads. Setscrew on the hex adapter securely holds
it in place over the axles.
These adapters are red in color.
Four hex adapters
Width: 12mm (15/32")
Height: 5.5mm (7/32")
Hole diameter: 5.5mm (7/32")