The DP-Calc 5815 and 5825 micromanometers allow you to easily make HVAC pressure measurements. These robust instruments can be used with Pitot probes to measure duct velocity. The DP-Calc 5815 is a simple to operate, hand held digital micromanometer for fast, accurate differential and static pressure measurements. The high performance DP-Calc 5825 can calculate flow and has data logging capabilities.