Crower utilizes Ti-17 titanium material in the manufacturing process of their titanium retainers. Although harder and longer to machine, the Ti-17 is 8-10 points harder on the Rockwell C scale for added retainer life over conventional 6AL4V titanium commonly used by other manufacturers. The result is added longevity and durability. Crower converted to Ti-17 about two years ago and has seen no wear due to excessive mileage or high rpm's. All Crower retainers are made in-house at Crower using the latest CNC machines to insure quality and batch to batch consistency. A typical Crower titanium retainer weighs about 50% less than it's stock steel counterpart. For example, the stock K20A2 steel retainer weighs a whopping 14 grams, while the Crower titanium retainer weighs in at 7 grams. For every gram you can reduce from the valve area (valves, retainers, keepers), you will pick up on average of 35-40 more rpm in valve control. So a 7 gram weight savings is equal to 280 additional rpm's before valve float.