Brinmar makes full length covers which are designed ½" short to slightly expose the coil and provide air circulation. Other manufacturers may have as much as 6-12” of coil showing. This is too big of an opening and it looks unappealing. In fact, the manufacturer is simply cutting costs by giving you a short cover. The standard industry width of a roll of vinyl is 54". Some companies will cut the roll in half and use this dimension to determine the height of their covers. When a hem and seam are added their finished cover would never be greater than 25". Brinmar uses the height of the air conditioner to determine the height of the cover and also adds additional material to the seams.