I just broke a speed-pro file fit ring the other day. Machine shop claimed he couldn,t get a single ring so he got me a hasting ring set for a cylinder, file fit also. put it all together and did a leak down on that cylinder. it would barely blow 60%. took it back out and found the second ring not touching the cylinder on almost 50% of its circumference. top ring wasn,t touching on 10% of its circumference. Googled the part # speed-pro ring i needed and jackpot. when it came in the mail filed it , put motor together and leaks 92%. Did i get a bad set? who knows, i have Hastings rings in my back-up motor and they leak great and work good.