DIN fitting was originally brought into line in the 1970s. It is an electrical connector, and its architecture has multiple pins under a protective circular sheath. Normally, a full-sized din connector contains three to 14 pins with a diameter of 13.2 millimetres. The term din connector doesn't refer to a specific cable. Instead, it requires all the connectors that meet the din standard. The circular connector is another name for din connector in computer electronics. It's also used for a digital interface such as musical instrument digital interfaces MIDI.

SAE adapters are sometimes used in power sports applications and automobiles and provide an easy way to connect different equipment. Generally, the adapters are designed to achieve minimal power loss and maximum current flow. One form of SAE adapter is quite common in cars and helps you light up your smoke.

BSPP and BSPT adapters are similar to NPT except for one important difference. The angle across the flanks of threads (if you sliced the fitting in half long-ways and measured the angle from root to crest to root) is 55 degrees instead of 60 degrees as it is for NPT. Thus an NPT male will fit into a BSPT fitting or vice versa but they will not seal. This is a popular fitting in China and Japan but is very rarely used in North America unless the equipment to which it is attached was imported. Thread sealant is needed to seal the male and female fitting together. Instruments have adapters to both male BSPT adapters and female BSPT adapters.

O-ring face seal (ORFS) fittings are a highly popular and reliable choice in hydraulic and tube connections. Well designed ORFS fitting provides a seal that is highly reliable due to its elastomeric seal and is one of the best choices for a leak-free connection.

JIC fitting is common in most fluid power systems. Both male and female components have 37 degree seats. The seal is formed by establishing contact between the male flared and the female coned seat. This is considered a mechanical connection. There are three components that make a tubing assembly; fitting, flare nut and sleeve. They are readily available, offering a large variety of sizes, shapes, combinations and materials. Sizes are consistent with SAE fittings which makes them easily interchangeable and identifiable. The absence of an O-ring makes them desirable in high temperature applications.

The weld fitting can be used in place of threaded fittings, so the risk of leakage is much smaller. Weld fitting needs not to be beveled for weld preparation. The weld metal can not penetrate into the bore of the pipe. Construction costs are lower than with butt-welded joints due to the lack of exacting fit-up requirements and elimination of special machining for butt weld end preparation.

SAE high pressure flanges are used as a reliable alternative to regular pipe and tube connectors. Their biggest advantage is the considerably higher pressure resistance for many sizes and the continuous pressure level of the high pressure series which can operate with maximum working pressures of up to 400 bar.