Re: Dual sim adapters
you cant have a single phone work with two sims at the same time. dual sim adapters are just glorified spare sim card holders. if you really need this, you need special phones that are in reality two phones “glued” together.
google voice is a good idea if you want a second phone number being auto-forwarded to another number. you dont need to install any app for this, just configure the google voice account settings. but yes, only in the US.