720p represents the entry point for displaying HD. 720p refers to seven hundred and twenty lines of resolution. The 'p' in 720p stands for progressive scan. The term progressive scan aptly describes how it functions, it refers to how a television builds up each image frame. It does so by progressively displaying each line of resolution in sequence. 720p is capable of a resolution of 1280x720, with a frame refresh rate of fifty to sixty Hz. The drawback with a 720p television is how it displays 1080p content. Due to it's line limitation, it cannot fully handle 1080p, which can result in a distorted picture. Although Sky (2010) broadcast their content in the 1080i HD format, a Sky+ box can be setup to scale HD content at 720p.