IEEE 802.11n-2009, commonly shortened to 802.11n, is a wireless networking standard that uses multiple antennas to increase data rates. It is an amendment to the IEEE 802.11-2007 wireless networking standard. Its purpose is to improve network throughput over the two previous standards—802.11a and 802.11g—with a significant increase in the maximum net data rate from 54 Mbit/s to 600 Mbit/s (slightly higher gross bit rate including for example error-correction codes, and slightly lower maximum throughput) with the use of four spatial streams at a channel width of 40 MHz. 802.11n standardized support for multiple-input multiple-output, frame aggregation, and security improvements, among other features. It can be used in the 2.4 GHz or 5 GHz frequency bands.