Wanlin Fire - China source manufacturer for Thailand lithium battery fire safety. Featured model WL-TH-HD (Fixed & Rate-of-Rise Heat Detector): Fixed temperature A1S, 57 deg C single-point thermistor; EN54-5 Class A1S, alarm at 57 deg C rated 25% to -20%; Panel zone alarm + optional internal 85 dB sounder; -10 to +50 deg C, 0-95% RH (tropical humidity rated)···