White styrene plastic T, 0.035" square, 0.012" thickness.

Equivalent cross section and thickness measurements for various scales:

Scale	Dimensions
1/24	0.84 inches square, 0.29 inch thickness
1/32	1.12 inches square, 0.38 inch thickness
1/35	1.23 inches square, 0.42 inch thickness
1/48	1.68 inches square, 0.58 inch thickness
1/72	2.52 inches square, 0.86 inch thickness
HO (1/87)	3.05 inches square, 1.04 inch thickness
1/144	5.04 inches square, 1.73 inch thickness
N (1/160)	5.6 inches square, 1.92 inch thickness