Starbucks ESPRESSO (espresso) according to the amount of espresso (shot):

Solo espresso is 1 shot of espresso, about 23ml

Doppio espresso is 2 shots of espresso, about 45ml

How many milliliters are in each of the two?

Expanded:

Shot is the unit of measurement of espresso, One shot means one espresso, Double shot is a double espresso, and the more shots you have, the more concentrated the coffee.

Starbucks is the name of a U.S. coffee chain, founded in 1971, and is the world's largest coffee chain, with its headquarters located in Seattle, Washington, USA. Starbucks retail products include more than 30 types of the world's top coffee beans, handmade espresso and a variety of coffee hot and cold drinks, fresh and delicious variety of pastries and food, as well as a rich and diverse range of coffee machines, coffee cups and other goods.