I have completed some extensive research into devices to help with Erectile Dysfunction.
One method that many reported successful in extreme cases of health problems such as Prostate Surgery, heart disease & diabetes is the Penis Pump.
There are two major categories of Penis Pumps.
1) Used only to enlarge penis size (cannot be used for ED)
2) Designed for Erectile Dysfunction. This model is designed to place a cock ring over the penis before removing the pump.