Product Description The Surly SingleSpeed Cassette Cogs are the definitive answer to quickly worn-out aluminium sprockets. They are made of highly refined CroMoly steel, and are therefore extremely durable. Technical Information: Material: steel (SCM415 CroMoly) Compatibility: 6-9-speed, 3/32" chains / Shimano freehub bodies Base Width: 4.35 mm Teeth: 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 Chain Size: 3/32" Features: CNC-machined, heat-treated ChroMoly steel high tooth profile suitable for cassettes steel without shifting frames Manufacturer Numbers: 13 tooth: FW2071 14 tooth: FW2072 15 tooth: FW2073 16 tooth: FW2074 17 tooth: FW2075 18 tooth: FW2076 19 tooth: FW2077 20 tooth: FW2078 21 tooth: FW2079 22 tooth: FW2080 Contents: 1 x Manufacturer: Surly 6400 W 105th St Bloomington MN 55438 USA derby@surlybikes.com Distributor: Cosmic Sports GmbH Leyher Straße 47 90763 Fürth Germany info@cosmicsports.de