Haw. Rev. Stat. § 481H-6: Door-to-door sales.

No door-to-door sales of water treatment units shall be permitted unless a copy of data, claims, and information on water quality and health effects, as used in the sales presentation, are made a part of the contract. As used in this section, "data, claims, and information" includes but is not limited to, graphs, charts, news clippings, and other supporting information.