Overview Product Description 239021 New-No Box; Martin 40BS20-3/4 Sprocket #40; 40 Teeth; 3/4"ID; . Item is New; unused; no factory packaging. Austin Surplus SKU: 239021 Location: GRG-R01-P06-S04-D-0002160 Product Videos Custom Field MPN 40BS20-3/4 Product Reviews