Wheel Bearing Kit, this is 1 of 3 common kits for a typical 3500# 1 1/16" x 1 3/8" boat trailer axle, always match all part numbers and double check the seal numbers or dimensions, they all look the same but are NOT interchangeable. 

Kit TRP-53581 contains the following:  Note: requires 2 kits per axle if doing both sides

(1) Inner seal  1.71" x 2.56" x .500 aka Transcom 17255, or National 47336 or 171255UC

(1) Inner Bearing Race L68111,  (1) Inner Bearing L68149

(1) Outer Bearing Race L44510,  (1) Outer Bearing L44549

(1) Cotter Pin