we have used these for years and love them! this should not be denied or washed away. if you need help finding your valve, click here. it is especially designed with safety features and force limits. had it been left to me, we would still have been spinning the same treadmill with plans to do it "next year". make sure to bring your camera to capture these "once in a lifetime" moments. at least five times this week i walked into the kitchen when i meant to walk into the bathroom. 