If you want the full version and license for commercial use,
you can purchase here :

https://staircaselab.com/product/ellternity/

File include : 

1. Ellternity.otf
2. Ellternity.ttf
3. Ellternity.woff
4. Ellternity Italic.otf
5. Ellternity Italic.ttf
6. Ellternity Italic.woff