I have an 08 Apex LTX 40th anniversary model 2 weeks ago I literally had to stop every 5 miles to warm up my hands! (so cold they hurt) Hand warmers did not work at all.(and we rode 150 miles that day) Anyway enough was enough, I did some research and decided to go with Rocks Yamaheater w/boost. OMG what a differance, first of all I thought my hand warmers were bad, but a quick check with an ohm meter proved otherwise( 7.4 ohms each grip) I installed Rocks Yamaheater w/boost which was pretty simple. Fired it up and was amazed, within seconds you start to feel heat! I have a craftsman laser digital thermometer, at idle with handwarmers on hi I got a reading of 138 degrees, couldn't hold on to them with my bare hands for more than a couple of seconds. I also have an 07 Attak which is basically the same sled, just for the heck of it I fired up the Attak put the hand warmers on hi, waited for the red "warmup" to go out, then ran the RPMs up to about 3000 for aroun a minuite and took a reading 70 degrees!! Rocks costomer service and ease to get a hold of is a major plus. Thanks Rock for all your help!!