Abstract: A low-pressure fluid flow control magnetic valve (cycler) device, system and method for use emptying the contents of bladder by a catheter. The device can be connected with a specified drainage tubing to function as a hydrodynamically balanced system (to empty into a typical two-liter collection bag). The cycler can be connected externally to a urinary catheter for hospital, clinical and home-care use for the emptying of the bladder of a patient through a catheter in a biologically more natural, filling and draining, cyclic manner. Fully automatic, modes of operation are provided for opening and closing this valve to empty the bladder of urine when appropriate or necessary. The modes of operation respond to normal human (or animal) body pressures, or are automatic with a manual override. This device is U.S.F.D.A. approved for human use and responds to normal human (or animal) body pressures to assist the detrusor muscle to function normally in spite of an indwelling catheter challenge.