Don't get me wrong, I like my MXDL burner when I need to pop a few hundred balloons and cut through 85 pieces of electrical tape and light a couple boxes of matches. But I rarely need THAT much runtime AND more importantly I wanted something smaller, so I picked up a scrap piece of 1/2" copper pipe at Home Depot for $3, an end cap for $0.79, and headed over to my local electronics store to find some smaller parts. I found a PC battery that is 7.5 V (but measured 7.2), and a really small rocker switch that happened to pop right into the pipe. I was more worried about size than runtime, so I am fine with the fact that the runtime is really low. But I can still several ballons and light several matches before it dims, so it's perfect for a 2nd burner. And it ALMOST fits into the battery compartment of my MXDL. Enjoy...