Used Stanley Technidea water level. $400 OBO This is a very sensitive water level instrument. Used for measuring a floor, slab or whatever you need to know if it's level or compare one spot to another or multiples.
You simply roll out the cord, let unit sit for a minute and turn the unit on. Hit the zero button and then move the yellow instrument box all over the area recording the measurement. Can also be used vertical with the extension rod.
I will only accept CASH. Not interested in trades. I can deliver if around the Lafayette / Breaux Bridge area. Just ask. I have used it to record flatness on concrete slabs and wood floors in houses. It can be used inside and while someone is underneath the house, readings can be performed while the person underneath jacks and shims the supports.