Click to expand Tap to zoom Metro 5MPBX MetroMax® Polyurethane Locking Caster, 5" dia. by Metro Sale $57.00 | / SKU M-5MPBX 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart PAIR IT WITH + Satisfaction Guarantee The Metro 5MPBX MetroMax® Polyurethane Locking Caster can be used with either the MetroMax or MetroMax iQ mobile posts to create a storage and transport unit. 300 lb. load rate.