The universal ILCOR AED sign has been designed in accordance with ISO 7010 for safety signs and shape. Colours and symbols are in accordance with ISO 3864-3. Its comprehensibility has been tested in accordance with ISO 9186-1, rev. 2007 and proved superior to alternative designs.

The sign is intended to indicate the presence of an AED, the localisation of an AED in a room, a container with an AED for public use, or to indicate the direction to follow in order to reach the AED. Its purpose is to assist in the rapid identification of an AED in cases of cardiac arrest.
The sign may be combined with additional symbols or letters, such as an arrow or the letters ‘AED’ or equivalents in different languages. Use of the full text, ‘defibrillator’, is not encouraged for reasons of visibility from a distance. Several examples of possible variations are shown below.

Size of the AED safety sign: there is, strictly speaking, no minimum or maximum size of a safety sign. The size is determined by the largest possible distance at which the sign must be readable and the light conditions: direct or indirect illumination, transparent signs with backlight, etc. The design principles for size and illumination are published by ISO 3864-1.