That would be nice
Great question! If you got this duplicate SIM as part of the beta, you can check out our Beta participants get DIGITS for life offer for details on how to keep that line for free. If you only want to use your main number on other devices (up to 5) you can do this at no cost using the DIGITS app on the devices you want to use the phone number on. If you want/need a separate SIM card (typically for devices that cannot use the DIGITS app) this is limited to one duplicate SIM card per phone number and is limited to the amount of mobile internet lines your account can support.