Matrix Ultra Pec Fly / Rear DeltMatrix Ultra Pec Fly Rear Delt The Matrix Ultra Pec Fly Rear Delt offers a powerful, comfortable way to strengthen major upper body muscle groups! The rotating grips provide smooth movement during use, while an angled back pad and delt grips optimize user biomechanics. The oversized handles reduce the need to adjust the seat position between pec fly and rear deltoid exercises. It even includes a heavy weight stack to accommodate strength training