I previously owned the Bathmate x30 and have reviewed it. Its a great penis pump for the money, but it was always lacking in the size department. Bathmate offers the goliath edition which is one of the largest water based pumps you can buy, but it uses the old rubber gaiter system thats not very comfortable to use in the bath, shower, really at all.
The new HydroMAX editions of their pumps have the new swivel gaiter systems, so you can do a complete rotation while pumping to see your progress. No water leaks, and its a lot more comfortable than anything else I have used so far.
For those who have the hercules, or the Hydromax x30, here is a comparison picture showing the different in size.
The HydroMax editions of the Bathmate pumps are much a huge improvement over the old style rubber gaiters. These feel good, and pump a lot more efficiently Theres also no more leaking, like I experienced with the earlier hercules model.
More to come on the hydromax x40 soon- waiting for more information to be released like the dimensions for max girth and max length.