They are, I have one in red.
It is only about 20% the brightness of green but that was a tactical decision. When playing multi day airsoft games you want to read not wave a target that screams come and get me.
I hear that the green can actually charge fast glow photo-luminescent pigment, but that is hearsay and I don't like the yellow greens so wont be testing it.
Any idea where to get these in the US?