The ESP110Q is a combined surge protector designed for 4-pair twisted telephone lines operating at a nominal voltage of 110V. It features full-mode bonding and equipment protection with enhanced low-level let-through voltage, meeting BS EN 61643 Category D, C, and B standards. The device has a maximum working voltage of 132V, a current rating of 750 mA per line, and an in-line resistance of 1.0 O per line with a bandwidth of 15 MHz. It provides very low let-through voltages across all conductors (188V at C2 test, 175V at C1 test, and 145V at B2 test) and can handle maximum surge currents of 2.5 kA per signal wire and 5 kA per pair under D1 test conditions. The ESP110Q is suitable for use from LPZ 0A (service entrance) through LPZ 3 (sensitive equipment protection) in broadband, POTS, dial-up, T1/E1, and DSL applications, offering space-efficient protection in lightning-intense environments.