There's only one version of the Lectra/San, Rick
However Raritan does make a similar device called the Pura/San for use in fresh water (the Lectra/San requires salt water). Instead of making chlorine naturally by charging the ions in salt water with electrical current as the Lectra/San does, the PuraSan comes with a chlorine cartridge through which the flush water flows. The cartridge lasts about a season...replacement cost is about $70. As for the SeaLand SanX...the price never includes the overboard discharge pump...that must be purchased separately, and you can't use an impeller macerator with it. It also requires the use--and storage aboard--of a nasty formaldehyde-based brew called TDX, that sells for about $20/gal at discount and only treats 4 cycles per gallon. Between the cost--of both the equipment and the chemical--and the environmental impact of the discharge, I don't recommend it.Defender does have the best prices on all of the above...but it's absolutely necessary to know what you're buying BEFORE you call 'em...'cuz they can only take the order, they can't give you any advice at all.