Important:The threaded stem size is 1/2"-13UNC x 1.5", Thread (US), the stud diameter of this wheel is 1/2",stud length is 1.5"(38mm), and it's imperial, not metric. It doesn't fit M12x1.5 pitch . Imperial 1/2"x13 TPI fits better.
Specification
Wheel Material:Polyurethane Rubber
Stem Diameter:1/2 inch (13mm)
Stem Length:1.5 inch (38mm)
Safe for All Floors: Working great for all kinds of floors including hardwood laminate, tile vinyl, stone, marble, concrete, carpet, rug and bamboo flooring.