10Pcs Bubble Spirit Levels Mini Circular Bullseye Bubble Level Small Round Spirit Level Measuring Layout Tools (10x6mm, Non-Adhesive)

Very small. Might need bigger if needed for visibility.

I have never seen such small mini bubble levels and, they are fantastic for what I wanted them for. I have mounted them behind each of my drills to assist in achieving a straight hole.

These are good, they are nicely uniform in size and indicate the level well. I use them in 3D printed components and they work well.

I bought these with the idea of gluing them to drill and other tools where having a horizontal line is useful. These are small enough to fit on a hand drill motor, but too small to be very accurate. A bit better than toys, but useful in certain situations.

I used these on some 3D printed tools for measuring at home and for similar industrial applications at work. They do exactly what you expect, and if well integrated in your design look pretty good as well.