This read-only INTEGER reports whether this wireless client is currently using a 20 MHz or 40 MHz channel width. An admin checks this to confirm whether a station is taking advantage of 802.11n's wider 40 MHz channel bonding for higher throughput, or is limited to the narrower 20 MHz channel. For example, a client stuck at cw20MHz(1) in an environment configured for 40 MHz operation might indicate nearby interference forcing the AP or client to fall back to the narrower channel.