When I first bought my used gas gas, I had to replace them after year and a half due to the inner reed was starting to crack. At first I had the boyseen dual stage reeds, and when i ordered them they sent me the single stage. I asked the guy at my local dealer if this change would affect the way the bike ran, he said that there should be no effects and that they would probably last longer. Well was he wrong, for one my bike did not feel the same anymore and the reeds only lasted me 3 months. The reed actually had a nice chunk missing from it that went into the motor. I went to the dealer again and ordered another set of reeds, but this time I made sure they ordered me the dual stage reeds. Now my bike is running back like it use to, and I have had them for about 9 months.