This 5" Suction Cup from Kupo is a rubber and silicone pumping-vacuum suction cup with a 3/8"-16 threaded bolt designed to create a secure, vacuum-powered mounting rig on smooth, flat surfaces such as those found on vehicles and walls. You can safely attach a ball head to this cup and then mount your camera, light, microphone, or other accessory directly on the 3/8"-16 male thread. This unit also features a vacuum-loss warning indicator for monitoring and verifying the presence of a secure vacuum seal.