It is lightweight, easy to use, easy to move, easy to distort, easy storage, can be hung flat, will not be affected by a long flat straightness, parallelism, not easy to rust.
97B-2 with three bubbles .
| Spec | Qty(pcs) | Meas(cm) | G.W./N.W.(kg) |
| 12"/300 | 60 | 31×28.5x26 | 14/13 |
| 16"/400 | 60 | 41×28.5×26 | 16.5/15.5 |
| 20"/500 | 60 | 51×28.5×26 | 18.5/17.5 |
| 24"/600 | 60 | 61×28.5×26 | 20.5/19.5 |
| 32"/800 | 30 | 81×24×16 | 13.5/12.5 |
| 40"/1000 | 30 | 101×24×16 | 16/15 |