Specification: 100mm x 45mm x 50mm or 4 inch x 1.8 inch x 2 inch 5 or 16inch (M8) bolt size Weight: 0.4kg. Max load: 50kg (110lbs) The recommended distance of each two isolators is 24 inch, e.g. 63-99 isolators are needed for a room aera of 215-322 sq ft. Easy To Install: The base has 1 bolt hole on base for rigid mounting when used for supporting machinery, easy installation on ceilings, floors, walls, ducts, etc. Wide Application: The shock absorber can be used in bedroom, studios, home theaters, houses, hotels, bars, karaoke room etc. Can be mounted to ceilings, walls, pumps. Colour: Black and Red Material: Plastic and Metal Package Contents: 4 x Capacity Spring Vibration Isolators Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.