(1)angle:can be stopped at anywhere within 120 degrees (2)1pc for the door less than 5kg,2pcs for the door with 12kg (3)material:zinc alloy (4)adjust the screws position to fit different doors with different weights (5)high quality (6)high strength and load capacity (7)precision mechanism to ensure light and smooth action (8)smooth opening (9)flap held at any angle (10)quick,safe and simple mounting (11)can be mounted also on aluminium frame flap doors