MidWest Universal Crate Casters (2 Pack) Universal dog crate caster 2-set | This is for two locking casters. If you need 4 dog crate casters you will need to buy 2 sets Fit most standard dog crates | Crate casters work best with larger dog crates Easy to Install | All hardware is included Dog crate rolling Casters can lock to keep your crate in one position Dog crate casters includes MidWest Quality Guarentee 1-Year Manufacturer's Warranty