NB-IoT
Narrowband IoT: a low-power cellular technology for static devices that send small amounts of data, with very good indoor coverage.
NB-IoT uses a 200 kHz channel and very low data rates (tens of kbps). Its strength is reaching devices deep indoors or underground, such as water and gas meters.
Why it matters for business
NB-IoT can give long battery life at low cost for fixed devices. It handles mobility poorly, and roaming support between countries is less widespread than for LTE-M: check before choosing it for international deployments.