Aeropro Impact Hammer Heavy Duty - AP17621 Grip for comfort and stability. Heat treated impact parts for long life durability. Positive action trigger and built-in air regulator for simple power and speed control. Screened filter air inlet to keep dirt and debris from damaging the tool. Standard quick-change spring for speed and ease of chisel change. Front exhaust. Recommended air pressure 90 psi. 4 Piece chisel set included.