Features & Benefits | User Manual| IEEE let-through rating and UL 1449 compliance The 'Institute of Electrical and Electronics Engineers' (IEEE) Let-Through Voltage rating is based on a test that subjects a Surge Protector to a 6,000 volt spike. The rating equates to the amount of excess voltage that reaches connected equipment. The lower the number, the better the performance of the Surge Protector is. Underwriter's Laboratory's UL1449 surge protection safety standard uses these ratings to help users gauge performance. UL's best Transient Voltage Surge Suppressor (TVSS) Let-Through Voltage rating is "300V".| EMI and RFI noise filtering Reduces line noise that can cause data loss and keyboard errors.| Lightning and Surge Protection To prevent damage to your equipment from electric power surges and spikes.| Fail Safe Mode Most other surge suppressors continue to let power through even after their circuits have been damaged, leaving your equipment exposed to future surges. APC's SurgeArrest fail safe, which means that once the circuit of an APC SurgeArrest has been compromised the unit disconnects equipment from the power supply ensuring that no damaging surges reach your equipment. |