They all work. They change the timing curves and rev limites. A buddy gave me one for my 400 but I took it off it raised the rpms and sounded to high. My quad is stock and its reliable and thats what I like. Look up in cheapcycle parts or motosport to buy the part. They have good prices.Just what the title reads. Post comments if you want to. Thanks.
Pro Com, Big Gun, Rick's, Other.