Flange with push-pull closure in accordance with ISO/IEC 24702 and IEC 61076-3-117 Var. 14, fiber optic coupling made of plastic, guide sleeve made of zirconium oxide ceramic (ZrO2) slotted for single-mode applications, guide sleeve made of metal (Ph-Br) slotted for multi-mode applications, compliance with EN 50173-1:2011-09 or ISO/IEC 24702 with regard to the limits for insertion loss, plastic housing and dust protection caps of the coupling flame-retardant and halogen-free, easy to install thanks to round wall cutouts with inserts for hole punching pliers available on the market, can be mounted on the front, industrial-grade metal housing with increased robustness, flammability class according to UL 94V-0, better chemical resistance