Nubian z9max uses cm Telecom's 3g mobile phone card, but uses a 4g package.

Hello, this phone supports dual-card usage rules:

(1) Only one telecom C network card can be inserted at a time. When inserting the telecom C network card, the mobile/Unicom card works in the state of 2G(GSM), and the default telecom C network card is the network card. If you need to use the mobile/Unicom card to surf the Internet, please switch in the dual-card settings. After replacing the network card, the telecom C network card is not available.

(2) When two mobile or Unicom cards are inserted, when one card works in 3G/4G state, the other card will work in 2G(GSM) state. The default network card is card 1. You can switch network cards in the "Dual Card Settings" of your phone. After switching, the network card works in 3G/4G state, and the other card works in 2G(GSM) state.

If you need help, please log on to Nubian official website customer service hotline.

Thank you for your concern and support for Nubian products. I wish you a happy life. Thank you.