Nitrous express kits
That's a very valid point Vitamin C brings up..... "way back" when I was in the nos loop we had a local guy who sold Top Gun systems that we ran. He had a "mother" bottle in his garage and we'd drop bottles off there so he could cool and fill them. I had 3 bottles so I always had a back up plan. I only used it at the track to get those "bragging rights" time slips :). You'd best do your homework prior to buying a system on where you are going to get your "next hit".