LB Agar (Lennox formulation) is a widely used general purpose microbiological medium designed for the cultivation and maintenance of Escherichia coli and other laboratory bacterial strains. Each plate contains approximately 20mL of agar prepared from tryptone, yeast extract, and sodium chloride, providing a rich nutrient environment that supports rapid bacterial growth. The Lennox formulation differs from the Miller formulation by containing a reduced sodium chloride concentration of 5 g/L, making it suitable for applications where lower ionic strength is preferred. This medium is commonly used in molecular biology workflows such as cloning, plasmid maintenance, transformation experiments, and bacteriophage propagation. The nutrient rich composition provides essential amino acids, vitamins, and peptides that support robust colony development on solid culture surfaces.