Don't buy these, they are way too small... The exact model used on the original prop is an LED-Lenser brand Flash Fire, model LL7596. If you Google just the model #, you will find a lot of sites that have offered them for sale in the past, but they all seem to be out of stock... The model was discontinued several years ago, and they don't seem to be easily found anymore... I managed to buy a couple off eBay a couple of years ago, but never found them since (but haven't looked all that hard...)
The entire Flash Fire is about 5 inches long, with the acrylic part being about 3.5 I think... (I can measure it tonight if you want) Obviously cut shorter on the prop to get that angle...
Nice work on the key though, I almost want one just made out of clear plastic like that, it's pretty cool looking. :cool