I assume you are getting this to fill up those tiny portable scuba tanks with high pressure air as it would be ludicrous to fill up a full size scuba tank with this hand pump. It took about 200 full pumps to get this comfortably in the green (not full) for a small portable tank. The first 50 pumps are a breeze, then when you get to 100 pumps, the weak will no longer be able to help. I'm 205lbs and am putting my body weight into the pump motion and I had to take breaks as only the last bit of motion was adding air as the pressure went higher. Pump feels quality and it works as intended, I just don't think people realize the amount of effort it will take to pump a small tank to full though it makes you appreciate and ration the air in the tank. I'm pleased the air had no odor or oil in it and there weren't any leaks so the pump works as intended. If you have another person to help pump, it will help a lot because you can take turns when somebody gets fatigued.