These devices are attached to the outside of the penile area and direct urine into a separate collection chamber such as a leg or bedside bag.

[citation needed] Penile external catheters/urisheaths combined with urine bags are preferred over absorbent products – in particular when it comes to 'limitations to daily activities'.

[3] 15% of long term users may develop skin injuries, including inflammation, ulceration, necrosis, gangrene and constriction of the penis.

[4] Sizing can also prove difficult for some men, leading to dislodgement of the catheter and urine spillage during voiding (commonly referred to as pop-offs or blow-offs).

[5] While the line of causation is not well established, urinary retention from inefficient elimination while catheterized may allow more mineral buildup and encourage crystal growth.

They range from a simple plastic cup to elaborate devices designed to collect specific volumes or types of urine samples at various points in the micturition process.

By 2008[update], technologies that did not require opening of the flight suit began to emerge, such as the "Advanced Mission Extender Device" (AMXD), which includes a pump for draining urine into a collection bag.

[1] The first American crewed mission did not utilise a urine collection device, with NASA having passed over the idea, as the MR-3 flight was expected to be too short for it to be necessary.

[6] A stadium buddy is an apparatus that consists of a collecting bag fastened around the leg and tubing that attaches to a condom catheter.

Stadium buddies have been used by sports and concert attendees for over two decades[clarification needed], and are also used by pilots when flying aircraft too small to carry a restroom.