The Lenovo T440 has an 802.11n WiFi standard which is better than most similar spec notebook PCs that have been available for more than two years. Most laptops of a comparable age and spec to it have an 802.11b WiFi standard. This portable PC also have 802.11a and 802.11ac and 802.11g WiFi standards.
An 802.11n WiFi standard is actually the best Wi-Fi standard amongst all laptops that have been on the market for around the same time as the T440.
An 802.11a WiFi standard is the worst Wi-Fi standard amongst similar types of notebook PC.