5pcs Round Bubble Level Mini Spirit Level Bullseye Level Measurement Instrument (15 X 6)

These are useful for tripod heads etc but the small 12mm ones are just too small to offer accuracy.

They are very accurate despite the small size and the circle around the bubble is recessed into the plastic so even if the black ink fades as some other reviewers have reported you could redraw it with a permanent marker in the groove. Got them to attach to a cordless drill.

Small and useful keeping my power tools level.so does exactly whati bought them for

Do what they are supposed to.

Absolute rubbish. The bubble goes into a dimple on the top and doesn't move until tilted by quite a distance. Fit for the bin.

used to level telescope - seems to work well,

Small, useful and easy to fit in tight spaces (a tripod top, for instance). I use one on a turntable. It's easy enough to centre. I was expecting a self-adhesive backing but certainly on the 12 x 6 ones I received, the back is just hard plastic.