CFR›Title 7›Subtitle B›Chapter I›Part 51›Subpart P›Subject Group Grades ContainsSections 51.1540–51.1543CorpusDaily eCFRDisplayed edition2026-04-24Last updated2026-04-24 Sections 51.1540 § 51.1540 [Reserved] 51.1541 § 51.1541 U.S. No. 1. 51.1542 § 51.1542 U.S. Commercial. 51.1543 § 51.1543 U.S. No. 2. Previous Definitions Definitions Next Metric Conversion Table Metric Conversion Table