VIVO Caster Wheels: Create your own mobile workstation, TV cart, and more with 2 durable caster wheels (set of 4). Safe for all types of floors, these casters are great for home and office use Please Note: If your VIVO desk was purchased prior to Nov 1, 2020, you may need the M8 caster set PT-ST-015C. The attached guide will help determine if your desk requires an M8 caster (PT-ST-015C) or M10 caster (PT-DK-020C)