These are the required installation kits for Thetford EasyFit Premium Plus toilets.

Your selection will depend upon your vessel's voltage, whether you choose to flush with fresh or raw (salt) water, and if you select raw water flush - whether you already have a pressurized raw water system onboard.
NOTE that, unlike the Eco toilets, the Premium Plus toilets already include the control panel switch and wiring harness.

Pressure (Fresh) Water Flushing -
By design, the Premium Plus toilet plumbs into the vessel's pressured drinking water system, utilizing fresh water for flushing. Fresh water flushing is generally preferred for its odor reducing properties.
For this application you should purchase the Pressure Water Flush Installation Kit. Pressure Water Kits include a solenoid valve for tapping into your water pressure system, with a fitting for attaching the solenoid to the toilet. Select the appropriate voltage.

Raw Water Flushing -
In applications where conserving fresh water is important, you can flush with raw (salt) water.
In this case, you should purchase one of the Raw Water Flush Installation Kits.

Most purchasers will require the kit which includes a 12 or 24 volt pump to pressurize the raw water, as these toilets don't have any suction capability for the flush water supply.
Raw Water Flush Pump Kits include a pump to pressurize the raw/salt flush water, and a hose fitting to connect flush water to the toilet. Select the appropriate voltage.

If you already happen to have pressurized raw water onboard, select the Raw Water Flush Kit without a pump. This kit includes only a hose fitting to connect flush water to the toilet. Just a plumbing fitting, there is no voltage associated with this kit. At this time, this kit (#38861) is only available by special order.