I copied and pasted this little bit from the bath mate website:
“the design of the bellows (the rubber part of the Bathmate) does not allow you to exceed the negative pressure threshold of 0.4 bar. Compare this to the FDA (Food and Drug Administration in the United States) which states that any device that uses more than 0.56 bar of negative pressure in Penis Pumps must go through FDA testing and approval before it is allowed to be sold in the United States. Similar rules equally apply in Europe and all around the world. Also, the Bathmate has a large cushioned area on which the unit rests while creating and maintaining negative pressure. This prevents the unit from hurting your pelvic area or damaging your skin. Our tests have shown that pumps which only provide minimal protection for the skin can cause significant damage, whereas some can literally penetrate the skin of the user if the pressure is too high. Think of it this way; in one of our experiments we bought 10 penis pumps. These were made up of manual pumps, electrically operated pumps and trigger gun penis pumps, all of which we then put through our Melon Test. The Melon Test was performed using a melon (as the name suggests) because a melon has similar properties as the human skin; rough on the outside, but soft on the inside. Eight of the penis pumps tested penetrated the skin of the melon. Another seriously damaged the surface of the melon, leaving visible marks and “Melon Bleed”, and the tenth penis pump, the electric one, generated so much pressure that it literally sank into the melon. We did test an eleventh pump, the Bathmate penis pump, and at maximum negative pressure it caused no harm to the melon.”
Here’s the link:
http:// ww w.bath-mate.com/penis-enlargem ent.php
They state their maximum pressure is 0.4 bars. If I did the math correctly, that works out to approximately 11.8 inches Hg. As the bath mate is the only pump I use, I have no idea if that number is good or bad. I will say that I max out each time I pump and have had no problems but then I have a tough penis, lol.