The RPEN-110 is a necessity tool that should not be missing from any fiber plant manager or fiber optic installing technician. The Visual Fault Locator (VFL) Pen has a visible red light source centered on 650nm. Tool sends visible light over a fiber strand with a 10mW power, good enough to reach distances of up to 10Km. The VFL tool helps either identifying a strand of fiber by checking the remote end for light or simply allow to notice if any fiber strand is interrupted (seeing the red light reflections). RPEN-110 has a solid metal casing and choice of continuous and glinting light modes. It also comes with a belt pouch. Two AA batteries are required to operate the pen, batteries are NOT included. Standard ferrule connector has 2.5mm, suitable for SC, ST and FC optical connectors. For 1.25mm ferrules a separate optical ferrule adapter must be purchased.