
Your body armour is made up of 3 key elements:
- The Carrier Garment (the bit you wear like a jacket)
- The Trauma Pads / Plates (often detachable from within pockets on the Garment)
- The Kevlar Panels (contained within the Garment itself)
Fitting - Make sure your vest is comfortable for you, because actually wearing your vest consistently is far more important than what particular type of vest you have. When you first put your vest on, it will feel stiff - vests do "break-in" after a few weeks or so of daily use. Try wearing it a little more snugly at first to hasten the break-in process. If there are any rough spots in the bended Kevlar, smooth out with your hands to break-in smoothly.
Note that you can adjust how low, or high, your vest rides on the front. You want coverage as high as possible, to the bottom of the throat, but no pressure on the throat. Test to see if it is comfortable to sit and lean forward - as much as you would while getting in and out of the back seat of a car.
The fit on the sides is largely personal preference - gaps between front and back panels gives better ventilation and concealability. An overlap has more bulk, but provides seamless protection, and possibly better support for blunt trauma protection on the sides.