Industrial Scientific T40 Rattler Portable Hydrogen Sulfide Monitor With Alarms @ 10/20 PPM. The T40 Rattler is a low-cost, maintenance-free single gas monitor designed to protect personnel from dangerous hydrogen sulfide gas exposure in the most extreme conditions. Despite its compact size, the T40 Rattler includes features usually found only in larger multi-gas monitors including a large, liquid crystal display (LCD), internal vibrating alarm, audible/visual alarms and simple push-button operation. The monitor continuously displays ambient hydrogen sulfide readings in PPM & will alert the user when gas concentrations exceed the preset low or high levels. Adjustable alarm setpoints, calibration gas values, choice of text-only display selected by the user. Also has a peak/hold feature to show the highest reading during a shift & includes a flip-cap calibration adapter.