Features:
Heavier weight can lower the center of gravity and improve stability.
Extends the distance of the wheel and makes your car more stable and cool.
This 1/10 RC car combiner is made of quality brass material, which is sturdy and durable, with a long service life. Nice workmanship increase strength.
This RC car brass combiner set is simply designed in small size. It is easy to install and convenient to use. 
Specifications:
Item Name: 12mm Wheel Hex Drive Hubs Combiner Coupler
Size: as the picture shows
Color: Black
Material: brass
Net weight: 12mm(49g)/15mm(56g)/(17mm(63g)/20mm(70g)/25mm(82g)
Compatible with:1/10 RC Crawler Car Axial SCX10 90046 D90 
Package included:
4 x Hex Adapter
4 x Extension nuts
4 x Bolts