This is the same blow off valve used with our FD RX-7 BOV Upgrade Kit.

This Blow Off Valve is CNC machined from billet aluminum and utilizes dual o-rings to seal the piston (no diaphragm to fail like most BOV's use). Connect to both the inlet or outlet nippels with 1" I.D. hose. Finished in black hard anodizing. 

Lifetime Warranty.   3 extra springs and shims for fine tuning included