from the Defender site, click on their page for SeaEra Electric Freshwater Marine Head, household bowl..

it does say "less than 3 quarts"

nevertheless, thanks so much again Peggy, I like the 1 liter much better. I wonder if it makes sense to have an electric flush, freshwater head if you do not have a water maker, our tankage is 110 gallons, and we can go about 10-14 days on that, depending on how conservative we are. I usually pee over the side (Bahamas), but not my better half, + a 12 year old. If the Head flushes a half dozen times/day, that would be 10-15% of our daily water use.

What are the advantages of an electric AND freshwater Head ... other than easy and no salt water smell, probably quieter ?

thanks, cheers, John