Duel fields where they are. Use both ends for so many situations. I started with a trisquare 41 years ago and it's only limited by the size of the crack, yuk can do it without a square too. The base itself is an indicator. I installed the base at a 12 inch stair garage sale and have the original tool to use anywhere on the job.
Portable Handheld Manometer π for Accurate Pressure Differential Measurement
5 Review
π Enhanced Precision with Backlit Professional Manometer for Differential Ventilation
6 Review
Digital multimeter RGK DM-12
6 Review
π¬οΈ Advanced 3-in-1 Indoor Air Quality Monitor with CO2/RH/Temp Data Logging and Audible Alarm - NDIR Sensor Technology
8 Review