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 bodiesBase Width:4.35 mmTeeth:13, 14, 15, 16, 17, 18, 19, 20, 21, 22Chain Size:3/32"Features:CNC-machined, heat-treated ChroMoly steelhigh tooth profilesuitable for cassettessteel without shifting framesManufacturer Numbers:13 tooth:FW207114 tooth:FW207215 tooth:FW207316 tooth:FW207417 tooth:FW207518 tooth:FW207619 tooth:FW207720 tooth:FW207821 tooth:FW207922 tooth:FW2080Contents: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