40 A 40 Tooth Plate Style Sprocket CNC Machined for the Peerless 100 Series 1" and 3/4" Differential. 

It has the 4 bolt hole pattern drilled and has a 2-1/8" ID to match the hub. 

Use # 40 Chain 1/2" pitch x 5/16" width. 

Black Finish is standard.