This is a complete kit of a breech to replace the simplified one in the venerable Italeri kit. You will need to cut the kit breech off at the joint in the front flange, after gluing together the barrel halves. The main advantage of this kit is all the firing-circuit detail on the top and right side of the barrel. I also have a breech for the Takom kits in my shop at
https://www.shapeways.com/product/8F7RFFB6M/m47-90mm-gun-breech-takom-1-35-scale?optionId=64788633
You can have it in FUD (the default setting) or FXD if you think the extra-fine layering is worthwhile.
The parts are sprued together for convenience when printing, and are best painted before the breech block is added to the rear. Everything should be painted white except the breech block which is uncoated metal, and the grip on the end of the breech operating lever, which is black rubber. The machine-gun tray should accept any of the plastic .50cal MGs on the market - my preference comes from the Academy US Machine Guns set.
As usual, wash all Frosted Detail parts thoroughly with dish-soap and warm water scrubbed gently with an old toothbrush, rinsing thoroughly with clean water afterwards. This removes any residual wax and oils left from printing.