Tire pressure gauge (guage, quick, coupler, staun airdown)
Looking into different ways to quickly adjust the pressure in your tires, and I came across a couple of different products. I don't know which would be the best to air down with.
http://www.tire-pressure-gauge.com/i...wPro15big2.gif
http://www.tire-pressure-gauge.com/i...&products_id=2
A couple of T fittings, chucks, hose, and you could hook up to all four tires.
EDIT: Forgot to mention that this one lights up and would make airing down for night runs a bit easier.
http://www.autosportcatalog.com/file...re_gauge_2.jpg
http://www.autosportcatalog.com/inde...:referralID=NA
Looks like you could change the gauge out on this one pretty easy to a low psi gauge.