Featuring portable, battery-operated design, OM-91 logs temperature, while OM-92 logs both temperature and RH. Temperature is measured to accuracy of ±0.3°C over 5–60°C range and ±2.0°C over full range of -30 to 80°C. Relative humidity is measured to accuracy of ±3.0% RH over 20–80% range and ±5.0% RH over 0–100% range. Suited for transportation applications, loggers feature user-configurable high/low alarms, LED status indicators, USB interface, and immediate, delayed, or pushbutton start.