The bait is 8 1/2 inches long and 2 1/8 inches wide. The Firstline Bait is only meant for the Firstline baiting system and will not work in any other termite baiting system.
The FirstLine GT Plus Termite Bait is just cardboard laced with a chemical that the termites eat and will not degrade much at all over time. There should be no issues if the bait sits for a few years without being used.
You really need to identify the brand of station that you have as the manufacturers make the stations specifically so another manufacturers product cannot be used in them. Also, the Firstline GT Plus Termite should only be used after termite activity has been confirmed.