Top-quality garage door springs made in the U.S.A. Few IMPORTANT starting points about Diamond Springs: We have been manufacturing garage door springs for over 2 decades. All springs are fabricated with high carbon Astm 229 class ii oil-tempered wire. We offer a Lifetime Warranty on our garage door springs On the off chance that you are like many other people, you most likely have given next to no consideration to your garage door springs.