We had some new tooling made up by Green Filter USA so we could incorporate a new locking flange design on our air filter. This is only available on the Mountune air filter, by the way. This new air filter is replacing the UK K&N that we previously used, in case anyone is wondering. We normally sell these for $59. Right now we're offering them for a limited time for $45. AND you get FREE shipping!! All you have to do is enter in promo code: flow at check out to get this awesome deal! The code can only be used once by each customer.