Cruz--I think the last one I bought was $65, but that has been about 4 yrs. ago. Talk to my buddy Dave Shadel at Performance Specialties and he'll fix you up. www.pspec.com---I own at least 3 different sizes of them for different size engines. The one that fits the OS 61FX also fits the TT61 Pro. Heck I bet you increase your R's by 1500. These things flat out work. I've used them for 10 years. Never heard anyone who tried them NOT love them.