Just the standard manual shut-off valve that UKFLIER has highlighted....not servo controlled (it's a back-up just in case the electronic side of things fails - also useful to stop fuel going to the engine during refuelling, etc).

Do a search for Festo and, from there, find where the nearest distributer is to you...or, if you're in the UK, go to Motors and Rotors website and buy one from Dave Wilshere - he stocks them.

Cheers,
Dick
England