Got one for Xmas. felt oblgated to use it last week installing a shower
stall. You have to get the gizmo level with a bubble level mounted on
top of it, obviously, for the laser line to be level. Well first. I had
to rig up blocks for it to sit on. Tried sticking it to the drywall
with little pins, similtaneously leveling it with the bubble thing. It
kept falling off the wall. Got it sitting level on blocks, with a nice
red line on the wall. went to position the shower base, my body was
blocking the light. Then a corner of the base was blocking the light,
had to raise the level an inch or so. Go get a shim? Grabbed my old
bubble level, laid it across the base, there, that's easy.

JohnK