gijoe85,
I have to agree with myoldyourgold and Stevo on this.. Honestly, can you think of one thing under the hood of your car that is plain old glass? I can't.
The unit you cited operates at 12 volts nominal between electrodes rather than 2 to 2.5 volts that a conventionally built drycell does. This means that the jar unit will be making a LOT more heat & water vapor than HHO gas. The "neutral" or bipolar plates in a drycell split that 12V up into a much more efficient and lower voltage per cell. This means more actual gas production and less heat generated water vapor. The fact that you came to this forum and asked about a prebuilt unit rather than asking how to build a unit or system should indicate to all that you would prefer a kit or semi-turnkey system- meaning that you're not really all that jazzed about learning the arcanum of HHO, immersing yourself in a life of experimentation and essentially are looking for a way to improve your mileage in as straightforward a manner as possible. If this is the case then I would advise purchasing a system similar to this one- yes it does cost a little more, but it gives you most of the rest of the bits and pieces (balance of system).
http://www.ebay.com/itm/11-PLATE-HHO...e9d817&vxp=mtr
Mike, a member on this forum, username "hhoconnection" sells high quality units and balance of system components. He is quite knowledgeable and can advise you on sizing, installation and set up. If you haven't already seen these (in the newbies section) then here is an introduction... view-source:
http://www.hhoforums.com/showthread....os-for-Newbies