
I mainly use LevelMatePRO; However, I needed an "old school" backup level to check that my camper trailer was level. It was also a replacement for a previous model with an adhesive backing that had fallen off the trailer. I just lay this on the frame to check the level side to side and then front to back. I didn't screw it into the frame or use glue. Just plug it in, check it out, take it off and put it in the tool bag. I want it to be magnetic but it doesn't have to be.

π CAMWAY 6 Inch Digital Caliper with LCD Display, Electronic Vernier Caliper, 150mm Stainless Steel Feeler Gauge, Plastic Digital Caliper Set for Zero Setting Inside/Outside Diameter, Depth, and Step Measurement Tool
3 Review

Kapro - 353 Professional Ledge-It Try & Mitre Square - For Leveling And Measuring - Features Stainless Steel Blade, Retractable Ledge, And Etched Ruler Markings - 12 Inch
23 Review

π Johnson Level and Tool 400EM-S 12-Inch Heavy Duty Metal Combination Square for Professionals, with Inch/Metric Measurements, Silver - 1 Square
8 Review

π² Johnson RAS-1B Johnny Square: Professional Aluminum Rafter Square, 7'', Silver - Top Quality with 1 Square
8 Review