NB-IoT-BC660

NB-IoT (Narrowband Internet of Things) technology is a direct competitor to LoRaWAN and SigFox and has a few advantages:

• higher speed 25.5 kbps up and down link
• single GSM cell can connect to up to 100 000 NB-IoT nodes
• single GSM cell can cover up to 10-100km rural and 1-10km urban distance
• can work up to 10 years on Lithium 3V battery if less than 200 bytes are sent per day

Note: All GSM cells which work with LTE can also support NB-IoT, but this requires new protocol installation and licensee fee, so not all operators provide it by default. You have to check with your local GSM operator if he offers NB-IoT. Also SIM card must have this protocol enabled. SIM with LTE may or may not work with NB-IoT, this depends on your operator.

NB-IoT-BC66-ANT has GSM antenna included. 
NB-IoT-BC66H has EXT1 and EXT2 headers soldered.

NB-IoT-BC66 modules are meant for embedding. Experience with BC66 technology is required. For research and development it is highly recommended to evaluate the technology with NB-IoT-DevKit first (before switching to the modules)!

Distance between EXT1 and EXT2 = 22.86 mm (0.9" )
Distance between EXT2 and EXT3 = 2.54 mm (0.1")

Important notice: Quectel made BC66 obsolete and it's replaced by BC660 which have same functionality and AT commands, but it's based on different processor, so the code which runs inside (if you put any have to be compiled with the new SDK for BC660) might need some changes. You can find the differences between BC66 and BC660 in this official document (mainly there is no autobaud in BC660).