Redundant SIM Slots Dual SIM slots provide redundancy and keep the device always online. Both SIM slots can be filled, you can choose whether to use SIM card 1 or SIM card 2, or auto select by Cudy. WAN Internet, 4G Backup Set WAN/LAN port as WAN to enable Cudy use the landline internet from WAN, and 3G/4G connection works as a backup to provide a sustained and reliable internet connection for you. External SMA Antenna connector Combined with 4 detachable SMA Antenna interface to connect outdoor cellular antennas for better and stable signal. 4G Band Lock 4G band lock make it possible to lock the 4G working frequency to one or several bands to keep the stability of operation. TTL Settings Support manual set TTL values to meet ISP's requirement(such as Verizon, Visible). Support set IPv4 TTL and IPv6 HL Values. DNS over TLS Support DNS Encryption with CloudFlare or NextDNS or Google, protects your privacy, prevents eavesdropping and manipulation of DNS data via man-in-the-middle attacks.