How To Select?  
Selecting an LED Display should be driven by the business or organizational objectives you hope to meet by purchasing an LED Display System.
Every LED display application is different, so it is important to choose the right Indoor LED Display. Below is a list of questions that should be asked when considering a LED Display. Answering these questions will help you chose the right display application based on your necessities.
LED Displays are specifically designed for indoor or outdoor use. There are two main factors that differentiate the two. First is weather durability. Outdoor displays are designed to function properly in extreme weather conditions while indoor displays are not built to the same environmental standards. The second consideration is display intensity. LEDs used for indoor applications are not bright enough to compete with outdoor ambient light conditions. Outdoor LED Displays are designed specially to be bright enough for outdoor environment.
The exact placement of an LED Display in reference to the viewing audience is an important factor in determining the right product for an application. There are two points to consider when choosing a LED Display based on where it will be installed. First, the placement of the LED display will affect the minimum and maximum viewing distance. Secondly, the angle at which the LED Display can be effectively viewed must be considered, this is referred to as the viewing angle. Often, different Led Displays have different viewing angles. It must be ensured that the intended viewing audience is within the viewing cone of the display
Understanding the communication wants is a very important factor in determining the right product for a specific application

Viewing distance is one of the most important factors needed to determine the correct size of the LED Display.

As a general rule: 1 inch of text is viewable up to 50 feet away 1 or 25mm of text is viewable up to 15m away . The following diagram illustrates at what distance a specific character size of the content on an electronic sign will be recognized and understood by a stationary audience.

However, if the target audience is moving, then another factor, TIME, is required. Based on our experience and research, an average of at least three to four seconds is required for a moving audience to adequately recognize and comprehend six to eight grouping of content on an electronic sign. For example, an audience will have three seconds or less to view LED Display signs with four inches of text. If the LED Display signs have too much content, then the reader will not have sufficient time to comprehend the entire content.