These tapered ring compressors from ARP are CNC-machined from 6061-T6 billet tube material and feature a true radius for each different bore diameter. They are also relieved for wire O-rings on the bottom. Type 3 anodizing is used for long life, and the bore size is prominently engraved in 3/4 in. high numbers for easy identification. Their true-radius design is far superior to conventional tapered devices and they're widely acclaimed by professional engine builders.
