This is a super easy and fast to make tool and it is 100 % recycled.
This water level is really useful for example when you need to paint a room of two different color horizontally, or you need to find the same level of two things far apart from each over, like two shelfs, or two paintings.

Step 1: WHAT YOU NEED

You only need two small transparent plastic bottle, a used bike tire (without any holes) and a pair of scissors.

Step 2: CUT THE BOTTLES

Cut the bottom part of the plastic bottles.

Step 3: CUT THE INNERTUBE

Cut a piece of the inner tube, long as you need it.

Step 4: ASSEMBLE IT

Place each open side of the inner tube in each neck of the bottles (like in the photos)

Step 5: FILL IT WITH WATER

Fill one of the bottle with water, keeping the inner tube without any fold and the over bottle at the same level.

Step 6: DONE

Is ready!
Is easier to use in two people (or otherwise you need to make an hole in one of the bottle and hang it up on a neil on the wall).

Hold them both FIRM on the wall for few second and mark the water level with a pencil.

The water level is always constant (communicating vessels principle).