Open Box Zeagle F8 2nd Stage (serialized), BlackSmaller mouthpiece with super soft silicone and color accented tear resistant Bite lugs Exhaust valve with improved dryness and lower exhalation effort Inhalation effort control knob for better grip and style Heat sink with improved materials and greater surface area to dissipate cold Zirconium plated inlet tube for increased corrosion resistance Inhalation diaphragm with improved response and tear strength Redesigned front cover and inhalation effort