The guy who i bought it off said 250psi. Obviously i know this may be him being missinformed when he bought it, but the price of the ninja was too good to pass up, 135 or 400. Unless of course the pump has been replaced for a 250 one at some point (not ashbys).
And strangely enough, having used both 135 and 400 in the past, this one does seem somewhere in the middle??