Provides a reliable temporary vacuum installation without drilling. The rubber vacuum pad will not leave marks or damage on most surfaces. Can be attached to flat or curved, smooth, non-porous surfaces. The red line indicator warns the user of any vacuum loss. The check valve allows re-evacuation without losing the remaining vacuum. The cross groove on the bottom of the suction cup provides strong suction. Suction: 4.5Inch-50kg Suction Cup Diameter: 4.5Inch Thread: 1/4Inch Hole / 1/4Inch Screw Vacuum Pad: Concave Pad Application: Suitable for flat or curved glass or objects (automotive glass) How to use: Clean the rubber pad and the object to be sucked Put the rubber pad facing the object, press the suction cup on the object, and press the blue plunger several times. When there is a red warning line inside, you can lift or move. Colour:B:Black Material:aluminum alloy Package Contents: 1 x action camera car suction cup 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.