Added these 4 casters (two of them with brackets) to my gas fireplace. I (or my wife) wanted to be able to move it out of the middle of our deck when not in use. I used a 3/8-16 tap in my drill press with line fluid to open up the existing holes (5/16-18) after removing the screwed in leveling pads. They work great. I put a lockable wheel on opposite corners. Now, with a full and heavy propane tank, my wife can spend the night with her girls and use it when needed.