I got an free Android app called Bubble. Has a regular level and a bulls eye bubble. Its extremely accurate with my Samsung S3 Smart Phone. I lay my phone flat in the refrig, on floor, on sink top. all dead on every time so far on auto.. The Big Foot Jacks are so nice. We pull in, hit auto level, and a minute later My wife and I just look at each other and smile. I hated leveling my toyhauler with the scissor jacks, what a PITA and my shoulders torn rotator cup (different area). LOL
My only scare is the ground clearance to jack. Has anyone a story to share about ripping one off or damage?