8 x 10.
6 hole collage mat with three windows at 5 3/4 x 3 3/4 and two at 3 3/4 x 5 3/4 and one at 6 3/4 x 4 3/4. this will fit pictures that are 4 x 6 and 5 x 7.
6 hole collage mat with five windows at 5 3/4 and one at 3 3/4. this will fit pictures that are 6 x 4 and 5 x 7.
6 hole collage mat with four windows at 6 3/4 x 4 3/4 and one at 9 3/4 x 7 3/4 and one at 4 3/4 x 6 3/4. this will fit pictures that are 10 x 8 and 5 