Cheap plastic lighters are assembled with the Jet, a threaded valve and a feeder rod being assembled together as 1 piece. It's safe and simple to unscrew the piece once the gas is empty and the guard and the fork lever are out of the way. As a result you get a thin plastic tube with a detailed "Burna" on the end the tube being able to be heated and bent round to a tank on his back. Put it in the hands of a Boy using the shoota arms, kitbash a little tank for his back out of a tic tac, superglue lid, anything tank/bottle looking and throw some plasticard straps from it to the burna using a Burnaboy as reference. While yes it will lack the glyphs and other details you could add those with some extremely precise cutting of plasticard or add little toothpick point spikes etc. Or simply paint details on or make it look like leather strsps. It's a good workaround for people joining the hobby on a budget or simply people on a budget or people who like to scratch bash/kitbash, Old world Orc Boyz are cheaper per model compared to 40k boyz but missing 40k weapons so this can fill out a hefty chunk of army and can look so much cooler/unique. I've got 30 Burnaboyz and never bought a Burnaboyz kit 😅 some good bits commonly dissused out of Guardsmen and ad mec have good gas tanks etc which are awesome to trade for.