The FTE-4000 TTI Hand Held Variable Optical Attenuator (VOA) is available in two models, with 40 dB attenuation level or 80 dB attenuation level to meet single mode testing requirements. Like the rest of the FTE line, the VOA has an onboard help feature. The FTE-4000 has a built in output power monitor to assist in setting the appropriate attenuation levels and a sweep mode which can scan the attenuation across desired levels. It is rugged with a splash proof housing with a highly protective boot. The FTE-4000 can assist in the testing of system budget compliance, balancing transmitter power and adjusting receiver attenuation settings.