The most difficult part of ED is venous leak. Many men prematurely lose there firmness. This can be caused by vascular conditions such as diabetes or medications for high blood pressure. Men that need help maintaining can use a penile adjustable loop. This loop acts like a tourniquet to close the veins down to stop venous leak. They work well to maintain an erection because they are adjustable to the amount of tension required to hold. 

Caution: Never wear devices over 30 minutes.