This is a replacement caliper mounting bracket for Kodiak slip on 10" rotors. The bracket will only work with the slip on rotors for Kodiak brake system, and will attach to the 4 hole mounting plate on your 3,500# axle. This is Kodiaks part number CMB-10-U-SS. This bracket is made of Stainless Steel so it will NEVER rust! The bracket will work on either the left hand or right hand side of the trailer. Kodiak offers a 6 year warranty on all of their stainless steel parts.