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.