Master Model is a company that makes turned brass aftermarket parts, specifically pitot tubes, refueling probes, gun barrels, and antennas.
The first thing I would like to point out is how good the packaging and instruction sheet are. The packaging consists of a zip-lock type bag while the part is in a smaller bag, keeping it from moving all over and getting lost as you work. The instruction sheet is very clear and easy to understand, detailing a mere 3 steps. Cut off original part, drill a hole (0.8 mm), glue in the new metal part. Just be careful drilling the hole, especially in 1/72. The bottom of the sheet has a 1/72 scale template of the barrel spacing on the wing. I just laid the wing down over it and adjusted the distance as I glued the barrels in with CA.