I bought these because the cobalt toolbox casters were junk and fell apart after 2 years of service. concrete floor. This is high quality! The castors also have mirror fittings for lubrication.
Pros
TOP PLATE SIZE: 4" X 4-1/2" | BOLT HOLE SPACING: 2-5/8" X 3-5/8" (slotted up to 3" x 3")