The 10" (25.4 cm) pump cup is a robust vacuum suction cup model. Pump until the red marker disappears to create exceptional grip on non-porous surfaces such as car bonnets and doors. Use it in combination with the 4-position tilt plate for interesting camera angles, and a camera safety strap to ensure proper safety precautions. If you need a smaller suction cup to mount your lighting or camera, the new 4-1/2" (11.4 cm) suction cup is recommended to fit in tight spaces where the 10" (25.4 cm) or 6" (15.2 cm) suction cups are too large.