Grade 7 ball bearing hinge, suitable for 30 minute fire doors up to 40kg, when used in conjunction with intumescent hinge pads. Suitable for 30 minute fire doors Doors up to 40kg Smooth ball bearing action Fixings included" Size L x W mm: 76 x 51 Knuckle Dia. mm: 11.0 Hole Dia. mm: 6.2 Thickness mm: 2' Knuckle Type: Ball Bearing Corner Type : N/A Material: Carbon Steel Finish: Polished ChromeSize 75 x 50 - 2 Pieces Timco Grade 7 Ball Bearing Fire Door Hinges - Polished Chrome in Silver