NOYES 2.5 mm adapter, VFL port
AFL’s (original called Noyes) 2.5 mm Universal adapter for the VFI (visual fault identifier/locator) port on the AFL's OFL250 OTDR.
You can insert FC, ST, SC connectors into this port and get a red laser output as a visual fault locator to identify macrobending, fiber breakage, leakage in a fiber.