GW-Instek-APS-9501-500VA-AC-Power-Source-GW-Instek-APS-9501-P-The-GW-Instek-APS-9501-is-a-dual-output-linear-AC-power-source-To-protect-the-GW-Instek-APS-9501-&-loads-from-unexpected-conditions-over-current-over-temperature-&-short-circuit-protection-are-standard-High-accuracy-&-low-distortion-are-maintained-at-true-RMS-&-lt-0-5-THD-respectively-P-P-The-GW-Instek-APS-9501-has-a-key-lock-feature-prevents-tampering-Three-separate-LED-displays-simultaneously-show-frequency