TSP-10 - Telephone line surge protector, in-line RJ11 jacks, LED indicator Controls transient over voltages to protect sensitive electronic equipment Meets UL 1449 safety standard LED indicator for off-hook and ringing on telephone line Easy installation: one RJ-11 male connector and one RJ-11 female connector Surge current: 8 x 20u sec of 500A, DC spark-over voltage: 160 - 240V, dimensions: 30mm x 80mm x 27mm, weight: 20g