Ground spring

1. Through the industry standard QB/T 2697 test 2. Through SGS, DGM detection 3. Through EN1154 door-closing device detection 4, the industry's first, independent research and development of environmental protection filler, waterproof, rust-proof, heat preservation, insect prevention 5. Both the left door and the right door can be used, without distinguishing between the left and right doors 6, can make the door two-way opening, one-way opening must be achieved by other means 7. Suitable for wooden doors, metal doors, framed doors and other door types