First Waterproof, Rugged, Wireless, Environmental Data Logger measuring temperature, humidity and pressure.DROPS transmit their readings wirelessly via Bluetooth® Low Energy to mobile devices over 100ft away. When you’re not in range, they continue to log conditions, and all new data is uploaded automatically to Kestrel LiNK app for iOS or Android when the paired device comes back in range. The D1 can store 13064 data points. The D2 can store 8165 data points. The D3 can store 6220 data points (collection of all the measurements at a set point in time).