Early fiber optic cables used color to help identify what type of fiber cable it was. For example, orange, black or gray was multimode and yellow meant singlemode. However, with the introduction of metallic connectors like the FC and ST connectors color coding became more difficult, so colored boots are now used to help identify the fiber type and end polish. The TIA 568 color code for connector bodies and/or boots is Beige for multimode fiber, Blue for singlemode fiber, and Green for APC (angled) connectors.