Known by a variety of names - cam and groove, cam lock, cam lever - these couplings can be attached to hoses, pumps, tanks, trucks, etc., as a very simple and leak-proof way to quickly connect and disconnect hoses without threading.
Cam Locks are used in a wide variety of industrial applications where frequent connecting and disconnecting is required. Typically used with larger size hoses (although available in sizes down to 1/2 inch), you may have seen them used on fuel delivery trucks at gas stations, or on milk and other "tanker" trucks or train cars.

These couplings are perfect for dockside and mobile sewage pumpouts for marine holding tanks. They are typically used in commercial pumpout applications, although larger vessels may carry a set of their own hoses along with a selection of cam lock adapters and plugs.
In use, a male adapter end is inserted into a female coupler and the cam levers are engaged. This seals the face of the male adapter against the flat gasket inside the female coupler, under high pressure.

In a typical marine scenario, a mobile sanitation pump-out service would lead a hose with a female coupler to a boat, screw a (Type F) male adapter into the holding tank deckfill, and push the hose terminal onto the male adapter. Easy! Fast!
When the pumpout is done, simply undo the connection, remove the adapter, and replace the deckfill cover. The female coupler on the end of the hose can then be sealed by inserting a (Type PL) plug into the female coupler and caming it shut.
Glass fiber reinforced polypropylene with 304 stainless steel levers and pins
Interchangeable with other brands of cam lever couplings
Flat, round EPDM gasket in female coupler forms a leak-proof seal with the flat face of the male adapter
Rings on cam levers can be secured to tabs on male adapters to prevent accidental uncoupling, if desired
Rated to 100 psi @ 0F, 125 psi @ 70F, 70 psi @ 150
Not recommended for use with compressed gases

The format of these couplings is standardized as follows:
Parts ending in A Male Adapter - Female NPT
Parts ending in B Female Coupler - Male NPT
Parts ending in C Female Coupler - Hose Shank (Barb)
Parts ending in D Female Coupler - Female NPT
Parts ending in E Male Adapter - Hose Shank (Barb)
Parts ending in F Male Adapter - Male NPT
Parts ending in CAP Cap for Male Adapter
Parts ending in PL Plug for Female Coupler