Key heads for utility rooms and control cabinets come in a variety of shapes and sizes, known as "profiles".
Dimensional Note: The dimensions in the product description refer to the dimensions of the lock that the key will fit, NOT to the size of the key itself. Some profiles are designed for locks of more than one size, so the size indicated may be a range (for example, 9-10 mm) and not a single number. All dimensions except ¼ inch bit and head are in millimeters.
Square
The square pin is a very common valve head shape…
... and a square rosette is a regular lock profile.
Universal keys and control cabinet keys usually have two or more square socket profiles. Some of them will also have different pin profiles on the stepped pin head.
The dimension in millimeters in the product description is the length of the sides of the square part of the lock or valve head, to which the universal key and the control cabinet key fit.
Each manufacturer chooses different sizes for their wrench, but sizes typically cover 5mm to 8mm pins or sockets.
Triangle
The triangular prism pin is another common type of lock. Locks or valves with triangular sockets are also relatively common.
Universal and control cabinet keys often have at least one triangular socket, and sometimes a stepped triangular pin head.
When the profile of a triangle is drawn in a diagram, it is represented by a regular triangle with pointed corners, but most service keys and keys for control cabinets, locks, and valves actually have triangles with cut corners.
The measurement in millimeters in the product description indicates the length from the top to the bottom of the triangular shape. Triangular locks or flaps that can be turned with utility keys and a control cabinet typically range in size from 8mm to 11mm.
Circle with fins
The ribbed profile, also known as the double key profile, is one size and is commonly used to unlock control or service cabinets. Oddly enough, this is not always stated in the product description, so check the tool, its image, or your supplier before purchasing.
If there is a measurement, it will indicate the inner diameter of the round shape of the lock (unless otherwise noted) in millimeters. Ribbed round profiles fit lock sizes from 3 mm (⅛ in.) up to and including 5 mm (13⁄64 in.).
Household nest
Many service and control cabinet keys are sold with a ¼" reversible bit (see illustration). What utilities and accessories for control cabinets are available?) and will have a socket or slot in which you can put a small screwdriver. Often the bit socket is inside another socket profile, usually a triangular or square socket.
Other service keys and control cabinet keys have bit sockets in the key body. Sockets are sometimes referred to as "bit adapters".
Some bit sockets have a small magnet at the base of the socket that keeps the bit in place during the task.
Month
Crescent-shaped socket profiles are sometimes found on service keys and control cabinet keys. Crescent pin profiles are not available for these tools.
The flat side of the profile provides the surface on which the key presses to turn the valve or block. If it were a circle, the key would simply slide around the circle, and the lock would remain motionless.
They are not as easy to use as square locks because the key socket can only be placed over the lock head in one direction. If the valve is in a hard to reach place, the key may not turn.
Cross
Cross socket profiles are rare, but they are present on some service and control cabinet keys. Measurement in millimeters from the top to the bottom of the cross.
