Send Open Tabs Between Different PCs Using Firefox
Using the Firefox Sync option makes it easy to sync various bookmarks, settings and more so as to have same unified Firefox experience regardless of the devices used. (You can also sync between different browsers, this though would require an add-on xBrowserSync).
Also when using Firefox Sync, it is no longer needed to copy paste web links of open tabs or email their links so as to access them...
How To Turn Off Firefox Sync For Specific Devices
When Firefox syncing is enabled, bookmarks, open tabs, logins, history and add-ons will be available on various other devices which are added to the sync list.
This is handy for ensuring a consistent cross-platform browsing experience. As long as Firefox is installed on different devices with the same account login, this data can be synced.
However, it may happen that a device is now no longer used...