Home biofeedback devices are handheld electronic devices that let you know how strongly you are contracting your pelvic muscles when you practice Kegels (exercises for the pelvic floor muscles). Muscle strength is detected with a vaginal sensor and displayed on the handheld component. Food and Drug Administration (FDA)-approved systems (such as Myself or the PFX Pelvic Floor Exerciser) are available without prescription. In other systems, you buy the vaginal probe and rent the biofeedback device by the month. The PFX device is available in a men's model that uses an anal probe.