| ①Strength of the coupling is equal to the welding type. |
| ②The influence of the weather is hardly received. |
| ③It is possible to use it also for the site of the fire strict prohibition. |
| ④The enforcement management can be done easily, |
| ⑤Lightening is measured by dividing into three. |
| ⑥A special tool is not needed with a torque wrench. |
| ⑦Because the part thrust out from the pile is small, the influence of the frictional force is a little. |
| ⑧The reliability of the quality is high because of the factory production. |
