TRAXXAS TRX4 TRAIL CRAWLER Aluminum 17mm Hex Adapters For Front/Rear - 20pc set - GPM TRX4/17X19/2  [TRX4/17X19/2]

That has :

Hex Adaper Cover-4pcs
Hex Socket Screw 19mm-4pcs
5mm Metal Washer-4pcs
M4x2.5x13 Screw Shaft-4pcs

Handbook volume:

device major function & use:

1. Extend the wheel-base by widening the width through the hex.
2. Self-lock design provides better protection whenever driving and switching.

Quality elements with modern CNC appearance and simple to take advantage of with satisfactory upgrade performance.

Cannot usage on initial tires, SIMPLY appropriate tires with 17mm hex.