The best way to determine the replacement bearing, race and seal parts needed for a trailer is to pull one of the hubs and remove them so their part numbers can be noted. Usually bearings and seals will have part numbers stamped or molded into them, as you can see in the linked image.
You can search our site using those part numbers to see if we offer them. You can also measure the spindles on the trailer's axle at the points B, C and D noted in the image using a precision caliper like... view full answer...