The concealed gun is commonly built into a bionic arm, replacing a large portion of the arm's internal mechanisms with the folding mechanism of the gun. This results in a bionic arm that is even less dextrous and lacks proper sensors, but provides a small submachine gun built into the arm, able to be folded out.
With the limb upgrade installed, you are at a +4 difficulty for any task requiring manual dexterity using this arm, and when sensitivity is required. In addition, to make room for the gun, the majority of the servos have to be removed, giving the hand a significantly weaker grip. When strength is in question, your hand acts as if you had
Weak -1.
The submachinegun fires
9 mm JHP from a magazine of 20 bullets. The magazine can be replaced, but the arm must be unfolded and the magazine is concealed inside the arm, making it impractical to reload the weapon mid-combat. It takes a full turn to replace the magazine. You cannot stress or take any other actions in that turn.