Light Made Right. Keystone has designed, engineered, and manufactured reliable ballasts and advanced lighting products for more than six decades. We have grown significantly from our simple beginnings following WWII by delivering innovative solutions that stand the test of time. Our quality manufacturing processes produce the very highest levels of reliability and we stand solidly behind every product that we ship. When you need a partner with the capability to turn around a new design quickly, or a supplier who reliably stocks the parts you need, trust Keystone. We’re as solid as the rock that inspired our name.