A must have for any bar is this cocktail strainer also known as a Hawthorne Strainer Long Pipe Handle cocktail strainer. The coiled springs help it fit easily into the mouth of your mixing glass or shaker and prevents unwanted pieces of ice, fruit pulp, etc. to go into your glass. It helps therefore ensure a consistent cocktail.
The spring / coil of the strainer can also be easily removed and comes in very handy in a mixing glass when you are doing a dry shake.