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.
99B with three bubbles and two sides milled base
| Spec | Qty(pcs) | Meas(cm) | G.W./N.W.(kg) |
| 12"/300 | 60 | 31x33.5x30.5 | 11/10 |
| 16"/400 | 60 | 41x33.5x30.5 | 13/12 |
| 20"/500 | 60 | 51x33.5x30.5 | 14/13 |
| 24"/600 | 60 | 61x33.5x30.5 | 15/14 |
| 32"/800 | 60 | 81x33.5x30.5 | 23/21 |
| 40"/1000 | 30 | 101x28x19 | 15/14 |