Product Specs:

• Brand: BMI Karts
• Material: Billet Aluminum
• Conversion Bushing:  1-1/4" Bore Hub to a 3/4" Bore Hub OR 1-1/4" Bore Hub to a 1" Bore Hub (SEE OPTIONS)
  
• Overall Width: 1"
• Fits any 1-1/4" Bore Hub
• Keystock for 1" : 1/4" x 3/8"
• Keystock for 1-1/4": Requires BOTH 1/4" x 1/4" AND 3/16" x 3/16"