Testo 510i differential pressure measuring instrument with smartphone operation, including hose set (Ø 4 mm and 5 mm) with adapter, batteries and calibration protocol. Handy and intelligent: the compact testo 510i differential pressure measuring instrument featuring professional measuring technology and smartphone operation for measuring differential pressure. Readings can be viewed conveniently on your smartphone/tablet via the testo Smart App and emailed directly. • Pocket-sized temperature and air density-compensated differential pressure measurement • Measurement of gas flow and static pressure • Bluetooth connectivity to free Testo Smart App • Magnetic holder for easy attachment