White styrene plastic T, 0.287" square, 0.085" thickness.

Equivalent cross section and thickness measurements for various scales:

Scale	Dimensions
1/24	6.89 inches square, 2.04 inch thickness
1/32	9.18 inches square, 2.72 inch thickness
1/35	10.0 inches square, 2.98 inch thickness
1/48	13.8 inches square, 4.08 inch thickness
1/72	20.7 inches square, 6.12 inch thickness
HO (1/87)	25 inches square, 7.40 inch thickness
1/144	41.3 inches square, 12.2 inch thickness
N (1/160)	45.9 inches square, 13.6 inch thickness