When you are about to purchase an LED screen, for indoor or outdoor, for advertising, retail, sport, rental & staging or information, it is imperative to ask for, obtain and comprehend a detailed specs sheet of the product offered. This document must always contain a minimum number of essential features like display size with and without any possible enclosure and with indication of the dimensions of the cabinet or module on the base of which the screen is composed by, graphic definition (horizontal pixels by vertical pixels), PHYSICAL pixel pitch (distance between the centres of adjacent RGB dots), resolution (number of pixels per square metre), type of LEDs used (whether SMD or traditional), brightness (in NIT, i e. candelas per square metre, > 5000 for outdoor use), IP protection rating (65 for outdoor use) and horizontal/vertical viewing angle. To this basic information other things should be added up, all very important to understand if the model is suitable. Total weight, power supply and maximum/average power consumption are required to prepare well the site and plan the total investment. In this regards also screen depth and maintenance access (front or rear) must be considered from the very beginning. More linked to screen performance are specifications like operating temperature (normally -20°C +55°C for outdoor use), relative humidity (normally 10-99%), refresh rate (> 3000 Hz is required for best TV shooting), contrast ratio (useless if not related to external luminance values), number of colour shades (you can obtain 281 trillions with 16 bit processing – which will prove high quality electronic control system) and colour temperature range. Something quite interesting that is not often included in the specs sheet is the character matrix, i.e. the minimum character height, maximum number of writing lines and maximum number of characters per line – often messages on LED screens are not readable because this matrix is not fully respected. Connected to eletronic control systems are video inputs and outputs. And finally it is highly recommended to get clear information about 2 extremely important topics. 1) what kind of product certification will accompany the screen and if the certificate is issued by the supplier or an independent, recognised laboratory; 2) who is the supplier/brand of LEDs, ICs, receiving cards and switching power supplies. The quality of the screen is given by the quality of the components used. At least the information about the LEDs must be provided with every possible detail.