I am a VERY satisfied user of Microlon aviation and automobile products. I own a F33A Bonanza with a continental IO 520 engine that has 1350 hundred hours on it. The compressions are still holding like a new engine and I do nothing but change oil every 50 hours of flight time. The TBO is 1650 hours on the engine and it appears that it will continue to run far beyond that. Which means a savings of alot of money considering that a new engine or factory remanufactured engine costs $35,000. So every hour that the engine goes beyond the TBO is money in the bank.