ARP 4.125" Tapered Billet Aluminum Ring Compressor 935116 The four components included in

The four components included in the Stilo YA0873 kit perfectly match your Stilo ST5 chin pad to stop air from coming in through the front air vents

5/16 in Shoulder

Stilo's Top Air system fits over the forward two holes and extends down the front of the helmet and just under the top of the visor

435 in Long

ARP 4.125" Tapered Billet Aluminum Ring Compressor 935116 The four components included inARP's ring compressors are CNC machined from 6061 T6 billet tube material and feature a true radius for each different bore diameter. What's more, they are relieved for wire O rings on 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. Standard stocking sizes from 3. 552 in to 4. 750 in (SAE) and 75mm to 95. 5mm (metric). The true radius design is far superior to