The suction cup can be attached to any smooth or convex surface which will allow it to form an air tight inner seal as a result of the interior air being removed and forming a vacuum. ldeal for attaching magic arms, support rods and φ75mm bowl mount. Once attached to a smooth or convex surface, such as glass, the suction cup can remain in place for up to 12 hours without loosing its vacuum seal. It is advisable, however, to check the cup and seal every 4 hours of attachment and use. The suction cup is ideal for attaching and supporting most cameras, camera heads and accessories with an appropriate screw thread. It is also designed to work with 3/8 Inch and 1/4 Inch threads and comes with a built in 3/8 Inch and 1/4 Inch converter screw. Features: - For Use with Spider Crab Vehicle Mount - Create Smooth Motion Shots on Vehicles - 1/4 Inch-20 & 3/8 Inch-16 Screws/Thread Mounts - 20kg Maximum Payload - Pump Button to Create Vacuum - Durable Aluminum & Rubber Construction In the Box: Model: IF-VS118 - iFootage VS-118 Spider Crab Vehicle Suction Cup (20kg Payload)