How to keep the spirit level？

How to keep the spirit level？

The spirit Level is easy to keep:  it can be hung or placed horizontally, and its straightness and parallelism will not be affected by long-term horizontal placement. And aluminum magnesium light flat ruler is not easy to rust, so it does not need to be oiled during use. If it is not used for a long time, apply a thin layer of general industrial oil gently during storage.