CALMINI gears are the STRONGEST available. Here's why: 1. Our gears are made in the U.S. from SAE 8620 alloy. They are NOT foreign made. 2. Our gears are designed to be the strongest (coarsest tooth pitch possible) combination of ratios. 3. They're designed and made for your application. They're not modified or have had rings welded to them. Do you realize what welding on a heat treated gear does to it??!! Our product is the best, and we have the data to prove it.