My father has owned a small engine repair shop for 30 years. Since every 2-cycle engine required a slightly different oil:gas ratio, he sought a product that would work in any 2-cycle engine. After all, it’s not practical to have 30 cans of mixture sitting around! That’s when he started using the Optimol products (for 4-cycle engines, too). The big companies threatened him and stated they would void his customer’s warranties if he didn’t use their brand of 2-cycle oil. With the Optimol warranty in hand, he took the risk and hasn’t used another product since. Moreover, he’s never had a warranty claim against Optimol. I have a 21-year-old Lawn-Boy mower (2-cycle) and a 10-year-old STIHL trimmer. Both purr like kittens. NEVER use anything but Optimol products, maintain your equipment, and you will be very happy!