AW-D212 4 in 1 smoke/heat/flame/LPG gas detector tester adopts two combinations of detecting heads, A and B. Head A can detect smoke and heat detectors, head B can detect flame, gas and heat detectors. The combination of two types of detecting heads can detect and test the sensitivity of various point-type smoke detectors, heat detectors, combined detectors, flame detectors, and gas detectors.