FIFTY-FIFTY ISCG05 Chain Guide 32-40T Alloy Aluminum(Black/White) The high molecular nylon parts increase shock absorb, wear life, and reduce friction and noise. Full machined alloy hardware(upper cage/bashguard fixing bolts). Adjustable upper cage with chainring range indicator. Wild range chainguide angle adjust by rotation within ISCG Slot. Easy install with M6*10,12,16 bolts and chainline adjusted by 1mm and 3mm spacers.