Block Connector (for N.C. Circuits) (490-0504A) Features Faxback Doc. # 17086 Handsome, durable, clear polycarbonate base, just like glass. Double-blocked mounts directly on glass for fast, reliable foil connection by using strong self-adhering UL-recognized double coated tape. If a single block is needed, simply break it off at the seam. Special nickel-plated clips and screws provide maximum protection against corrosion. Each block has a lip on its side to protect the foil from slipping out of place thus reducing ground shorts. Used to complete the circuit between the foil and any protective closed-circuit alarm system.