Who needs UL or sales tax? All you need is a website, email, and Palpal account. I would bet this company is not a legitimate business.

The information is confusing on the site.

Found this under FAQ:
http://tankless-water-heaters.ecrater.com/help.php
What about quality control?
All Marey products meet the high standards of UL, and are inspected for quality before they are shipped. Marey Heater Corp. has been in business for over 50 years and has one of the highest and most respected reputations in San Juan, PR.

San Jaun, Puerto Rico

I could not find the company listed at UL but it may have been me.
http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/index.htm