Classroom Chess Sets – Best Use: Competition
For most classes the 20" square vinyl rollup chessboard with the standard size 3 3/4" pieces is ideal. These are conveniently available in just two styles.
We highly recommend green chessboards for the classroom since green is calming for extended periods of concentration.
If you have a smaller surface area to work with and need smaller chessboards than the 20" boards, there are a few options. See the 16.5" folding cardboard style, and 17" vinyl rollup boards. For extra small, there are even 14" vinyl rollup boards (called an Analysis set, since it's still good for study, but not for competition play).
From article Selecting Chess Sets for the Classroom