For MTRJ fiber optic modules or 2 modular jack inserts. For systems: Ackermann, AMP / tyco Electronics (Slim Line (SL) series: 110Connect Jacks, Toolless Jacks / Standard 110Connect Jacks), Brand-Rex, CombiNet, EFB Electronic, Telena. For 2 fiber optic modules from the system: AMP / tyco Electronics MTRJ. Pitch: (WxH) approx. 14.8 x 20.4 mm. Without spreader. Check compatibility with other manufacturers not listed according to the pitch specified. You can find further information in the Communication Systems manual or on the Internet.