P-38 can opener

The P-38 is a small, lightweight, disposable, foldable alloy steel can opener that was issued with canned United States military rations from its introduction in 1942 to the end of canned ration issuance in the 1980s. Originally distributed in the K-ration, it was later included in the C-ration. A larger later variant is known as the P-51.
As of 2025, the P-38 can still be found in military surplus stores.
The can opener is approximately 1.5 inches (38 mm) long, and consists of a short rectangular metal handle with a small, hinged metal tooth that folds out to pierce the can lid.
A notch just below the hinge keeps the opener hooked beneath the rim of the can as the device is "walked" around to cut the lid out. A larger version called the P-51 is somewhat easier to operate thanks to the greater leverage it can generate.
The designer of the original device that acquired the official U.S. military designations "U.S. ARMY POCKET CAN OPENER" and "OPENER, CAN, HAND, FOLDING, TYPE I", commonly known as the P-38 is unknown. In spite of widespread claims that the P-38 was designed in a 30-day whirl of inspired effort by the U.S. Army Subsistence Lab in Chicago in 1941, a fully fledged version of the device (differing only in the hole for attaching to a lanyard being on the opposite end of its body) appeared in a 1924 edition of Popular Mechanics. Described as being “designed for campers and Boy Scouts”, it is featured in use in a photograph, with an accompanying full-view illustration. Readers were invited to receive more information on the item at that time by writing to Popular Mechanics, Chicago.
The P-38 was preceded in US military field rations such as the K-ration and C-ration by then traditional twist-key can opening, where a provided key was inserted in a tab and twisted around a can to peel away a metal sealing strip.
P-38s are no longer used for individual rations by the U.S. military, as canned C-rations were replaced by MRE rations in the 1980s, packed in plastic pouches. The larger P-51s are included with United States military "Tray Rations" (canned bulk meals). They are also still seen in disaster recovery efforts and have been handed out alongside canned food by rescue organizations, both in the U.S. and abroad.
J.W. Speaker Corporation of Germantown, Wisconsin, was one of the early contractors for the military P-38, producing them in the millions (stamped "Speaker USA"). The opener was also manufactured by Washburn Corporation (marked "US Androck"); and later by Mallin Shelby Hardware inc (defunct 1973) of Shelby, Ohio, variously stamped "US Mallin Shelby O." or "U.S. Shelby Co."
The P-38 is operated by pivoting its cutting tooth to its designed 95-degree position from its stowed position folded against the body. The opener is held in the right hand by the flat long section, with its circular notch hooking the underside of the can’s rim and the cutting tooth pointing downward and away from the user.
The right hand is rotated slightly away from the user, causing the can lid to be punctured. The opener is then advanced slightly towards the user and the motion repeated around the can.
As the folding tooth only locks in one orientation, operation is reversed for left-handed usage, an ergonomically much less efficient procedure.
A similar device that incorporates a small spoon at one end and a bottle opener at the other is currently employed by the Australian Defence Force and New Zealand Army in its ration kits. The Field Ration Eating Device is known by the acronym "FRED". It is also known widely in its derogatory backronym, the "Fucking Ridiculous Eating Device".
Another similar device was included with British Army "Operational Ration Pack, General Purpose" 24-hour ration pack and "Compo" Composite (14 man) Ration pack rations. At one stage they were manufactured by W.P. Warren Engineering Co. Ltd, Birmingham, England. The instructions printed on the miniature greaseproof paper bag they were supplied in read:
The Swedish army also employed a similar variant of this opener. Its official designation is M7481-021000 Konservbrytare Mini which was distributed with field rations.