<br>Loading Capacity:30KG per caster,good for heavy chair. <br> <br>Using for wooden chairs, small sofas，bench,etc <br> <br>Safe for all Floors: Our ball castors don't damage your expensive hardwood floor,it could not leave a track <br> on your floor. Because our ball castors will help to protect it. <br> <br>Humanization design： Good finish,roll smoothly,easy installation and 360 degree rotary.You just only use 4 <br> screws to fix the caster wheels on your chair. It is a expensive way to made your chair could move anywhere and be convenient.