The Philex 27867R is the ideal tool for Improving bad or weak DVB-T signal. Connecting directly to your aerial, this device shows a reading on a scale of 1-4 of the green LED lights of your terrestrial freeview recption, allowing you to adjust your aerial to find the best alignment as easily as possible. Please note that this product is designed for the improvement of the reception of terrestrial broadcasting. this product is not intended for satellite signal testing. You may also require 9V battery to power this device, sold seperately. Main Features: Finds the best aerial positon for tv signal Clear & simple LED reading display Connects directly to your aerial Short F lead, F plug, and coax adaptor included Technical Specifications: Frequency Range: 40-862MHz Input level: 50-90 dBµV Weight: 159g Power: 9V battery / 5-12v plug 3.5mm jack Instruction Manual/Spec Sheet 1 Year Guarantee Included