A-216850-AI 50 IDLER SPROCKET 17T 1/2One New Aftermarket Replacement #50 Roller Chain Idler Sprocket 17 Tooth, 1 2" Bore This aftermarket replacement idler sprocket is designed for use with #50 ANSI standard roller chain. With 17 teeth and a 1 2" bore, this sprocket serves as a chain guide and tensioning component in agricultural equipment, conveyor systems, and other chain driven machinery. Idler sprockets like this one keep roller chain properly aligned and tensioned, reducing wear and