Built-in strong adhesive: Supports up to 5 kg, offering higher adhesion power than conventional suction cups. Features a vacuum locking ring that effectively prevents air pressure from loosening the grip, ensuring a secure hold. No drilling required: Installs in seconds by simply placing it on the surface and pressing the safety lock switch. Resistant to water vapor and humidity, suitable for use in bathrooms and other damp environments. Made from high-quality ABS material for durability and portability. Lightweight yet sturdy design ensures long-lasting performance. The suction membrane has memory retention; if relocating, simply rinse under tap water, allow to dry, and reuse. Ideal for use on drawers, hooks, and various hanging applications. Compatible with glazed ceramic tiles, glass mirrors, patterned tiles, frosted glass, lacquered wood, and other surfaces with less than 1 mm of unevenness. Material: ABS. Suction cup diameter: 6.4 cm. Dimensions: 6.4 x 6.4 x 5 cm. Package includes: Glass door knobs.