On last Wednesday’s re-entry after a 14:00 stope blast on the 1450 level, two Ventis Pro5 units showed 2–3 ppm H2S for about 90 seconds in 94% RH at 6C, while tubes and fixed heads read zero, so I held the crew at the refuge until we verified. Which handhelds are giving you dependable alarms in wet, cold headings, and how are you setting thresholds, pump vs diffusion, and telemetry tie-in for quicker muster without compromising risk?