Many dealers sell WR Long, Kubota and Land Pride 3rd function valves. Kubota and Land Pride each make kits, but do not make duplicate kits. You can buy one or the other, not both. WR Long is an aftermarket co. that make the kits for many models/brands.
I checked them all out and I ordered the Kubota because it has steel tubing going down to the front. Just preferred it over the hyd. hose. But that's for an L 4240, don't know about Kubota's M kit. But if a clean look and tubing is something that might be of interest, I'd check them out.