櫻井伸之 4 The air pump can be used, but the amount of weight that has to be applied to inflate a bicycle tire until the required 80 psi was so high that makes the air pump very unstable. So it easily tips over, making you to lose balance. Since I realized that, I leaned my body against a column while using the air pump, but since the force that has to be applied is so strong, when the air pump tipped over, a big part of my weight was applied to the arm leaning against the column, and immediately I felt a loud crack and a strong pain in the middle of my upper arm. Eight hours have already passed and the arm still hurts, so I think that unfortunately the air pump can't be used safely, so it should not be allowed to be sold. I strongly recommend not to buy it.