Backup Ring Contoured Material Buna N For Use with AS568A Dash No 138 Thickness 0.053 in Radius 0.129 in Axial Thickness 0.045 in Actual Width 0.086 in Actual Inside Dia 2.143 in Cross Section Shape Rectangular Durometer 90 Shore A Durometer (Hardness) Rating Hard Color Black Temp Range -40 Degrees to 250 Degrees F Package Quantity 50