The nut blades are used to penetrate the back of the oben fastener and open the door with the replaceable pin. rounded edges prevent steel from tearing; on the surface, the blades are finer milled to achieve the greatest possible flexibility. 8mm at 72mm lock distance (room doors) 9mm for panic locks and fire doors 92mm 10mm at lock distance (front doors) Create a party-ready atmosphere with this colorful LED lighting. Easy to install and perfect for events or home decoration.