That seems kinda interesting, Although it seems like there's some things that can happen to make it ineffective or dangerous as such it says create a vacuum, expand and grip besides the fact that its an air pump it seems that the spring grip is the vacuum module which would be difficult to maintain an erection get this to have enough of a vacuum by pumping it and get it to grip without rubbing yourself raw. It going to create a small vacuum in a small area of the base and likely fight to create at [words=https://shop.mattersofsize.com/products/sizegenetics-penis-extender]traction[/words] let alone you may lose the vacuum if you lose an erection.. I still think the [words=https://officialhydromaxpump.com/?uid=6&oid=2&affid=98 ]bm[/words] is the safer way for girth then this, but if you try it let us know your review so others can get some info.
Also the details in the description say they are 3d printed to size of the user as far as i know that's not the kind of thing ebay would be able to do.. that and idk if you have been 3d printed objects, they tend to be rough with ridges without a lot of work and care so that could open the possibility of bacteria growth on the device.