Garage Door Corner Supportt which is a fitting of garage door.
with very high quality and safety
have 6 sizes
steel thickness:2.0mm/2.5mm
spec.38mm*38mm/30mm*30mm
the bracket is suitable for using in horizontal track
L=550mm/1000mm/1500mm/2000mm/3000mm
the angles are made of 2mm galvanized steel
https://www.autodoormotor.com/industrial-door-motor/garage-door-parts/garage-door-corner-support.html