Helical Cut  
    15 x 50 
    Quiet
    5-10MPH increase

This is an easy install, however, we would recommend  replacing the bearing at this time and make installation a breeze along with maximizing performance! You will probably need a new gasket too.

Bearing Gasket

You can still phone in and order if you prefer. 831.484.1921 M-F 9am-5pm Pacific Time