Suit GEN 1 Hayabusa Made from T-6 6061 CNC aluminium billet block these are the strongest on the market. An extra feature that sets these apart form the others is these have the chain adjustments marks milled into them @ 1/4″ adjustments…no more guessing…unlike the other copies cats on the market. The most note worthy feature that these have, that NONE of the others have is….the bolt in the picture… stays with the bolt on extension. The others on the market require that the bolt be shorter or longer when you move the axle. This means you have to remove and replace the bolt with different sizes. NOT THESE!!!! The bolt stays and allows the axle to move the complete length.