US letter paper - at 8 1/2 x 11 inches in three weights - 20 pound, 28 pound and 32 pound
US legal paper - at 8 1/2 x 14 inches in three weights - 20 pound, 28 pound and 32 pound
Sold in packs of 50 for lower freight costs.
Metric equivalents (approximately):
20 pound = 80 gsm
28 pound = 100 gsm
32 pound = 120 gsm
Letter paper dimensions = 215 x 279 mm
Legal paper dimensions = 215 x 355 mm