Adjustable Height: Each headboard stabilizer's length can be freely adjusted by reducing or increasing the number of screws: 30-40 mm (no screws), 47-64 mm (1 screw), 64-87 mm (2 screws). Instructions: Adhere the base with double-sided tape to the headboard, then hand-tighten the EVA pad side until it firmly presses against the wall. Recommendation: Install 2 upper mounts to prevent shaking and 2 lower mounts to prevent movement. If you find a loose bed affects your sleep, causing squeaking while you try to sleep, and causing serious discomfort during both sleep and waking hours, this product will help solve those problems – it's incredibly useful! Wide Application: Made of metal and EVA, this adjustable threaded bed frame anti-shake tool can be used in many places where the center of gravity is unstable or prone to shaking, such as beds, cabinets, chairs, sofas, etc., placed against the wall. Package includes 4 bed frame anti-shake tools and 4 screws. Super glue and EVA protective pads are pre-installed on the bed frame anti-shake tool for easier and more convenient use.