Introducing revolutionary IST technology! Incredibly realistic intermittent suction provides a lifelike "milking" sensation for the best blow job of your life! Customize your pleasure just the way you want it! Enjoy realistic intermittent suction by itself, or thrust to enjoy deep-throat stroking action-whatever you're in the mood for! Become bigger and thicker than ever before! The crystal-clear tube is designed for a firm grip and has a convenient ruler to gauge your expansive growth and a magnifying section to view your increasing thickness. Supple lips on the stretchy TPR pleasure-donut help create a tight seal and firmly caress your shaft if you chose to use your PDX Elite Blowjob Power Pump as a stroker. Advanced IST Technology = Lifelike Intermittent Suction - Enjoy maximum pleasure with realistic intermittent suction that automatically milks your shaft and feels just like a real oral sex experience. Surround your penis with an incredibly stimulating vacuum-action suction that snugly tugs you to ecstasy! Operating Instructions: Power On - Press the top button to turn on. There are 2 modes of suction. IST starts in the first mode, continuous suction. Press the button again to switch to the second mode, intermittent suction. Pressing the top button will alternate between continuous suction and intermittent suction. Press and hold the top button for 3 seconds to turn OFF. Quick Release - Press and hold the bottom "R" button to release suction, or pulse the "R" button for extra stimulation. Alternate release method: Press down on surrounding skin to break suction seal. During intermittent suction, the "R" button will flash on and off as suction is automatically pulsed.