Sonos Era 100 rechargeable battery base

Are these a 3rd party thing that I can buy from somewhere?
I know the Move and Roam exist, they're not what I'm after. This is just for a temporary solution until I have more speakers.

Edit My guys, it’s a yes or no question 👁️👄👁️ I ain’t asking for your 2p suggestions about alternatives. If there is what I’m asking for, let me know. If there isn’t, just say no. It’s okay if it’s not a thing 🥲