The testo 750-2 includes a single probe voltage testing, built-in flashlight, and GFCI test function. The 750-2/-3 can perform GFCI Circuit tests on AC outlets. When performing a GFCI circuit test, a 35 mA load is applied to the circuit. The testo 750 vibrates ensuring that the GFCI circuit test is active. The testo 750 voltage testers are the first instruments to include an all-around viewable LED voltage indication. All three models include low input impedance, phase sequence, continuity test, and meet CAT III 1000 V CAT IV 600 V safety standards.