A pistol style grip for Harbor Freights Central Pneumatic airbrush. I used a couple springs from old pens inside the trigger to help the trigger return I didn't try without them but it might still work. Since the brush is a double action I had to add a screw to press the air while the trigger pulled for paint. Feel free to make this better as this is my second time using cad and just wanted to make something to make it easier for my partner to use the brush with her hand pain.