Lighting Stands are the basic equipments in Studio, but they must always moving for change the lighting angle, sometimes when you using 1000ws lamp head with a big softbox, it is not easy to move, but if your light stands have those wheels, it is not a big deal. Descriptions : Tube size:22mm universal Material: Metal and rubber Feature: Add this set of 3 smooth rolling casters to your favorite light stand or boom stand for more mobility in the studio. The heavy duty foot activated brake lock on each wheel gives extra security and keeps equipment safe. The 75mm wheels give smooth rolling to make moving your stands a cinch. The wheels are universal suitable for all light stand,especially suitable for Selens Light stand. Smooth rolling wheels make moving stands a snap. Locking wheels give safety and security to your equipment. Suitable for the light stand which diameter is less than 22mm. Package contain: professional castor wheels*3 pieces Notice: The light stand and boom arm in picture are not included.It is just for show the light stand wheel. Thank you for your understanding.