The RH300 is a compact meter that is ideal for field applications. Simultaneously displays relative humidity, air temperature and dew point or wet bulb. Calculates T1, T2 differential (air temperature minus external probe temperature) using optional probe (TP890), and T2 minus dew point. Compact meter is well suited for field applications. Unique sensor cap closes to protect to protect meter during storage. Advanced features include Data Hold, selectable Auto Power Off, and MAX, MIN, Average reading. RH300 complete with batteries.