Ah, I know exactly what you’re describing. Those small glass tubes with three tiny ball bearings are typically spindle or vial level indicators—but let’s break it down carefully.
Likely Identifications
- Jewelry or Watchmaking Bearings
- Tiny ball bearings are often shipped in small glass tubes for precision watches or jewelry machinery.
- The glass tube prevents loss or contamination.
- Spirit Levels / Bullseye Levels
- Some mini bubble or spirit levels (used in microscopes, cameras, or small instruments) contain ball bearings instead of bubbles in a liquid-filled tube.
- The balls roll to indicate level or tilt.
- Calibration / Laboratory Use
- In labs, small glass tubes with metal balls may be used for centrifuge balancing, viscosity testing, or microfluidics experiments.
- The balls move predictably under motion or tilt, allowing precise measurement.
💡 Tip for Identification:
- Check if the tube contains liquid or is dry.
- Liquid → likely a tiny level indicator.
- Dry → likely spare bearings for machinery or experiments.
- Size of balls: very tiny (~1–2 mm) → precision mechanical use.
If you want, I can make a visual guide with pictures of each type so you can match exactly what you have. Do you want me to do that?
