WeWentSimRacing 
Moza Racing 4 to 3 Hole Base Mount Adapter
by Moza Racing
The 4 to 3 hole base mount adapter is compatible with R21/R16/R9. It matches a 3-pin bracket and is made from CNC machined, high-intensity steel for durability.
The 4 to 3 hole base mount adapter is compatible with R21/R16/R9. It matches a 3-pin bracket and is made from CNC machined, high-intensity steel for durability.