Freon leak detectors trigger on R22, R134A, R404a, R410A and all halogenated refrigerants (including , , HCFC and mixtures). Audible and visual gas leak indicator and dual battery indicator. react to all halogenation. This includes but is not limited to: After rotating the switch, the detector is ready for use. 1-7 level selectable sensitivity Response time: 3s Working temperature: 0℃-52℃ (30℉ to 125℉) The highest sensitivity to all halogenated refrigerants: 0.21oz/yr Battery life: about 50 hours of normal use Operation mode: continuous and unlimited Fixed probe length: 7.87 (in) Dimensions: 1.37 x 1.37 x 5.90 inches Warm-up time: about 6 seconds Reset time: two to ten seconds Power supply: 6V DC, 4 AAA alkaline batteries. (not include) Colour: Black Material: Plastic Package Contents: 1 x detector Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.