To manage this process, NGG provides NTS entry-level capacity and NTS output capacity that NTS gas shippers must reserve to deliver gas in and out of the system on behalf of customers. National Grid Gas (NGG) is the owner of the transmission (TO) and the network manager (SO) of the gb National Transmission System (NTS). As part of its role as TO, it is required to ensure that NTS capabilities are sufficient to meet the gas flow needs of NTS customers. Entry capacity is provided in quarterly, monthly or daily bands through a series of long- and short-term minimum auctions. Exit capacity is provided, in annual and daily quantities, primarily through an annual application window, although short-term capacity rights may be acquired if capacity is available on the day before and in the day. The ability to enter provides the daily right to inject gas into the system until an agreed rate. The output capacity offers the right to remove gas from the NTS until a supposed flow.