True Details has made a very nice 20mm Vulcan cannon for the Hasegawa F-104 kits. All the parts are well molded, have nice detail and clean up very easy. 13 parts make up this set including: Gun body (one with the shroud and one without), gun nuzzle, bracket, reservoir, hatch, control box, duct, regulator(X2) and gun body support(X2). You will have to use aftermarket or the kit barrels and neither the kit nor this set includes the braces that stabilize the barrels so you will have to make those.
One note - I wanted to use this in the new Italeri F-104 kit but it does not fit without a good bit of surgery although it gives me an excuse to pick up a Hasegawa kit now!!!
Overall, I would recommend this set as it has much more detail than what you get with the Hasegawa kit and it comes at a very reasonable price.
I would like to thank Squadron for supplying this set; IPMS for letting me review it and all of you for reading it.