The red is most common, I don't know the specs of the yellow. More chemical resistant maybe? I would also recommend at least 3/8 ID hose with 3/8 NPT fittings for better flow. The Flexilla is nice and lightweight, but they do like to coil a lot. As long as it's at least 3/8 ID I would have no trouble using it. I have a similar 1/4 ID that I use just for Nailers. If your going to run an oiler on your line you don't really want to use a rubber hose though. The oil will permeate through the hose and make a slimy mess on your hose, attracting dust and well...just make a mess. Not that I did that or anything...No No my friend told me that. Yeah that's it, my friend told me.
I included a pic of the Milton Type V coupler next to the standard 1/4 Type M. The brass is the standard 1/4 Type M, and the other is the Type V, it's a noticeable difference. They are available in 1/4 Npt threads and the 3/8 Npt(have to match what's on your hose). And of course in male and female options of each. The female couplers are also compatible with the standard 1/4 Type M male.
To be more precisely accurate...the Type V male will not fit a standard Type M female coupler, because the Type V is bigger. But the Type V female coupler will accept a 1/4 Type M male but not the 3/8 Type M male.
I think there is a little confusion happening. The Type M have 1/4 and 3/8 bore size, and threads, not interchangeable bore size. The Type V have one bore size and 1/4 and 3/8 NPT threads hence the NPT.
The Type M, 1/4 and 3/8 bore will not interchange. If the 3/8 Type M was available in a 1/4 NPT threads...that would be good too. But as far as I can tell there isn't such a thing. The 3/8 is only available in a 3/8 NPT Threads.
Conversely, the Type M 1/4 is available in a 3/8 NPT. But you still only get the flow of the 1/4.
Everyone I know and the shops I have been in all use Type M 1/4. Which the Type V coupler accepts fine.
Clear as mud now???
