IMPERIAL STEM SIZE: Our caster are standard 5/16" with 18 TPI,Coarse Thread (US), the stud diameter is 5/16" and the stud length is 0.79"(20mm), if your stem socket is METRIC M8, this caster is not suitable. 3 INCH LOCKABLE CASTERS: The heavy duty casters set of 4 with brake feature a locking design that it can brake the rotation of the caster only, but the stem is still moveable for direction. WIDE APPLICATIONS: These caster wheels can be used for a multitude of applications Including: Flight Cases, Instrument Cases, Dollies, Tool Boxes, Light Machinery, Equipment Stands, Mobile Workstations, Speakers, Cabinets, Stands, Amps, Electrical Enclosures, Furniture etc. VALUABLE PURCHASE: The package comes with few Nylon Lock Nuts for usage. PROTECT YOUR FLOORS: Our 3 inch heavy duty caster have a soft polyurethane rubber coating that makes them glide easily on any type of floor. They absorb shock and vibration, protecting your floors from scratches and marks. Hirate Heavy Duty 5/16" Threaded Caster Set of 4-A must-have in any home.
-Our caster are a practical solution to moving heavy pieces of furniture, as well as many other heavy items. They feature a 360-degree rotating design and locking for more safety.
-The Caster are covered in soft polyurethane rubber that protects your floors and make them glide smoothly on a wide range of surfaces.

Features
>【SINGLE LOCKABLE CASTER 】
-- With brake, effective to stop and fix the device and prevent it moving to hurt others.
-- The brake locks the Caster ONLY and the swivel is still moveable
>【Solid Steel Riveted Axle】
--Precision Ball Bearings for smooth rolling and Swivel Bearings For Smooth Rotation
【360 Degree Swivel and Roll Smoothly】
-- Very convenient to transform to any directions, and spend little strength to move on.
【Quite Rubber Basement Caster】
-- There is no mark when moving, and no hurt to your floor board.
【Widely Use】
-- Perfect using at home, office, or for industrial devices.
-- Such as coffee table, book shelves, shoe bins, toy bins, under-bed storage, shopping carts, workbench.

Specification:
*Stem Type: IMPERIAL SIZE
*Stem Diameter: 5/16"
*Stud Length: 0.79"(20mm)
* Caster Type: Threaded Caster
* Caster Diameter: 3"(75mm)
* Caster Width:0.87"
*Installing Height: 3.8"
*Installing nut size: 5/16"-18x0.79"
* Caster Material: Polyurethane
*Bracket: High quality steel - galvanizing
*Double Bearing: Steel ball bearing
*Total Load Capacity: 550 lbs
4 x 3" Stem Casters with brake (each caster with SINGLE brake)
4 x 5/16" Threaded Nylon Lock Nuts

WARNTING TIPS: THIS IS IMPERIAL STEM 5/16", NOT METRIC M8, PLEASE KINDLY CHECK YOURS BEFORE PURCHASE, THANK YOU.