SFS series Single Speed Freewheel1/8" Chrome PlatedSuitable for BMX and Urban bikesFits 1/8" chains16-22 Teeth sizes.2 pawl mechanismBall bearingFits to ISO threaded hubs 1.375" x 24 TPINote: Always apply a little grease to the threads when fitting.Use TLSF2 Freewheel remover to extract. 2STTLSF2 SFS series Freewheels are also available in 3/32" chain type options,and Mini SFX (M30) Screw-On 13-15T, 1/8 and 3/32 types.