Martin E50SF102 QD Bushed Solid Type B Triple Strand Roller Chain Sprocket, 2-15/16 in Dia Bore, 20.661 in OD, 50 Chain, 102 Teeth, 5/8 in Pitch, Steel
QD (quick detachable)is a sprocket where a tapered bushing is bolted into the taper bore that is machined in the sprocket. When installed this bushing is compressed onto the shaft providing a tight grip.
Martin Roller Chain Sprocket, QD Bushed Solid Type B Triple Strand, 2-15/16 in Bore Dia, 20.661 in Outside Dia, 50 Chain, 102 Teeth, 5/8 in Pitch, 20.296 in, 4-5/8 in Hub Dia, 1-1/4 in Length Through Bore, Type SF QD® Bushing, Steel