Here's a typical example of a Catalog Number. First, (A) the series designation, the dash (-), then (B) the wheel diameter, (C) the wheel bearing, and (D) the wheel type.
Please remember, if an accessory, such as a WK wheel brake is to be added, a suffix number is required, i.e. 200-6UV-WK.

The first two numbers represent (A) the wheel diameter, the next three (B) the tread width, the dash (-), (C) the bearing symbol, and (D) the wheel type. Of course, order spanners separately.
Please suffix WS wheel seals as follows: 06200-UL-WS.