The 70 Mu is the first caster of its kind. It utilizes one high-precision chrome steel radial ball bearing per caster, and two self-lubricating journal bearings in an efficient arrangement that allows for exceptionally smooth operation and twice the load rating of typical “high-capacity” chair casters, yet with lower costs of production and 30% less weight as compared to our 70 Okina Mu caster. The standard 11mm friction sleeve stem mount fits 95+% office/gaming chair sockets (not IKEA).