This extremely rich medium was developed by Botstein, D. et al for obtaining high yields of lambda bacteriophage in liquid lysates containing 3.5 times more tryptone and 4 times more yeast extract. tryptone, yeast extract and sodium chloride along with sodium chloride Tryptone and yeast extract provide nitrogenous compounds, vitamin B complex and other essential growth nutrients. Sodium chloride maintains osmotic equilibrium. This media is very rich in tryptone and yeast extract. It contains 1.5%agar, hence ready to use to prepare plates