ZKT-SRB Please log in to see price or purchase this item Quantity discounts available QuantityPrice SKU: ZKT-SRB MANUFACTURER: ZK Teco Product Details Security Relay Box (SRB) An external relay box which is connected to the door lock. SRB connect with readers via Wiegand SRB provides better securi... Product Details Back Product DetailsSecurity Relay Box (SRB) An external relay box which is connected to the door lock. SRB connect with readers via Wiegand SRB provides better security than wiring readers to door lock.