IMPERIAL STEM SIZE: Our caster wheels are standard 3/8" with 16 TPI,Coarse Thread (US), the stud diameter is 3/8" and the stud length is 0.79"(20mm), if your stem socket is METRIC M10, this caster is incompatible, please check before buy. | SINGLE LOCKABLE CASTERS: The package includes 3 Standard caster and 2 CASTERS constructed with brake pedal, it can brake the rotation of the caster only, but the stem is still moveable for direction. | HEAVY DUTY CASTER WHEEL: Our chair casters are made from industrial-grade steel, precision ball bearings, and durable polyurethane chair casters, can support up to 500 lbs for 5 pack 2 INCH casters, can be widely used for most chairs and other furniture with IMPERIAL STEM 3/8" only. | SATISFACTION GUARANTEE:The package comes with set of 5 caster wheel(2 with brake, other 3 without) and few 3/8"-16 thread Nylon Lock Nuts. | QUIET & SMOOTH ROLLER: Made of high-tech elastic polyurethane, with double bearings are quick rolling and the surface is sleek,wouldn't get stuck by crumbs,hair, wouldn't damage on floors.