The Erect-Tech Manually Operated System (MOS) is the manually operated version of Uromax Vaccuum Therapy Device. It is a highly durable design to provide great use time after time. It provides you with almost immediate erections. This is one of our most popular models sold. In addition, we provide you with 2 penile sleeves when you order with us (exclusive to U&Me Time). Also please call us directly if you have any questions, as we want you to be successful with your Vacuum Therapy Pump.