K51m-3in1 auto door closer hinge-full mortise type Combines a hinge, door closer and hold open in one product Overall features: 1. Advanced engineering- 3-in-1 combines a hinge, a closer and a hold open in one product. 2. Zero maintenance- stainless steel construction, no hydraulics, no leaking oil. 3. Full adjustable- adjust closing force(0-6), adjust closing speed, installation complete. 4. Strength- door duty loading max. 240lbs (110kgs) 5. Durability- 1, 000, 000cycles testing, many years of maintenance free operation. 6. Code compliant- ada, ul listed r26997, ansi/bhma a156.17 grade 1. 7. Material- 304 or 316 stainless steel Spec: 4"&4.5" For k51m 4.5"*3pcs in a box. 874kg / 0.775 cbm / 1 plt (mim 1cbm) For k51m 4.5"*2pcs in a box 1098kg / 1.111 cbm / 1 plt