Trying to figure out the terminology and make sure I understand it correctly.

Got my Fasse solenoid valve ordered from Sloanex which should be here later today.

I see Lundell plastics has a variety of wireless remotes.

http://www.lundellplastics.com/planting-products/freeflo-wireless-remote-category.asp

I've figured out that M designates momentary and L designates latched. Then there are single, double, triple, variations or combos of momentary and latched by all the different model lettering's.

The one at the top left and bottom right have relays with them what are the relays for ?

Would appreciate having my thoughts checked.

Momentary means powered only while the button is being held down. Button must remain depressed to hold valve open to run ?

Latched is like a toggle switch. Press button once and release it keeps valve held open until a button is pressed again to shut it off  ? 

Is it a direct connection remote to solenoid or do I need a relay to handle the load ?

My understanding is the Fasse valve has a harness that requires a push button to be held for it to operate and when released it shuts off.  If I couple it with a latched remote control that will hold it open until I press a button again ?

2 function latched I could use 1 function to hold solenoid control valve open and the other to turn inoculator off and on. There are times I want to control them independently.

Remote would save the hassle of a lot of wires and switches but this would be it's main singular use at this time.  Could this remote control be used for any thing else around the farm?

Anybody have one of these units ? How are they for longevity and durability.

Looks like a call to Lundell will be in order but just wanted to get my understanding of how they work correct before I decide if I want to go this route or not.