It is a 6 gallon Atwood LP unit.
It is pilot fired, which is good or bad depending how you look at it.
The electronic models use no gas until the thermostat tells it to heat the water.
The pilot model uses the pilot flame to maintain the temp.
Works well too!
Once up to temp, the burner does not come on until you draw enough water off (add cold water) to trip the thermostat.
I ran it for two weeks on pilot only.
The burner came on once, for about 15 minutes after I enjoyed a 6 minute shower.
I have the shower head set to 1/2 gallon per minute flow, but can adjust up to 1.25 gallons per minute.
Plenty of time to get clean, and a couple minutes to just enjoy the water.
All told, I used about 5 gallons of water (after the basic shower, I turned up the volume) I was going to measure exactly how much water I used, but I forgot to close the holding tank valve, and it all just ran away
I'm quite pleased with the system, I have a 21 gallon fresh water tank, so I'm good for a long weekend.
I did a lot of research into the type of water heater, and plumbing system that would best serve me.
The portable water heater units are okay, but pay very close attention to the gallons per minute at stated max temperature.
Boils down to hot shower = a dribble.
Lukewarm shower = light stream.
Cold shower = good volume.
Besides that problem, each time you want hot water, you have to set the whole rig up, then wait...not for me...
The 45# pressure my water pump maintains makes a huge
difference between a dribble, and an enjoyable shower.
The shower head is also very important!
Get a water saver that mixes air with the flow.
The "on demand" water heaters are the next step up.
They are permanantly mounted and plumbed, like a traditional system.
Their downfall is similar to the portable units, in that gallons per minute determines everything!
A small efficient unit usually can't keep up with the volume most folks are used to having for a shower, etc.
Well, it can, but the water doesn't have time to get hot enough...
The slower the flow through the coils, the longer it has to absorb the heat...faster it goes, the less heat it absorbs.
I have nothing against these units, I think they're great, but trying to fit one capable of doing the job in a small trailer is difficult.
The good ones are large, need a good sized exhaust port, and are anything but inexpensive.
If I had to do it again, I would save my pennies and buy a gas/electric unit, as opposed to the straight gas unit I did buy.
Since most camps have electric anyway...
Then again, over the life of the camper/Rob the gas savings may/may not account for the much higher dual W/H?