Mega 9-speed compatible machined and pinned super duraluminum. M970: all 3 rings mount to 1-piece arm/spider, plus middle chainring utilizes titanium teeth with carbon-composite reinforcement (also acts as shifting ramps). M960: all 3 rings mount to 1-piece arm/spider. M952: rings either mount 4-bolt (spiderless) outer chainring or to a 5-arm spider *(5-arm rings are also for XT-M750 cranks). (AA or V) series mates 22/32t, (AB or W) series mates 24/32t for shifting compatibilty.