This is simply the best axle on the market today. If you are tired of snapping your weak stock axles on the trail or in the sand, RCV axles should be your next purchase. These axles are equally comfortable on the race track, whether that be endurance, rocks, or short course. The Pro Series II has the same strength as the original Pro Series, but is designed to give an alternative option to suit the needs of different applications and conditions such as mud and endurance racing.The Pro Series II features a sealed outboard CV with a new accordion style boot made from high strength materials! Tests prove our Pro Series XP Turbo front axles to be 2 times stronger than the OEM shafts. Direct OEM fit replacement. 100% manufactured and assembled in the USA.