Left is front, right is rear. I could lock them on, or lock them off, for doing front digs, rear digs, etc. I could also shut the rear or front valve half way and use them in a sort of proportioning valve. I went with these because I hate having more and more electrical crap to worry about. I could set them overnight and not worry, etc.
I think these valves can be had for less than $20 each...