We have lovingly crafted manufactured and tested the rings here in the uks best riding spotswe then gave them to elite riders such as josh bryceland marc beaumont and scott mears to ensure quality chain retention at the highest speedswe use lightweight and durable 7075 t6 aluminium to ensure maximum endurance so that your chain stays where it is supposed toospecificationavailable in 32t and 34tcolours burgtec black use in conjunction with clutch rear derailleur for best resultsno need to