A cocktail strainer is a metal bar accessory used to remove ice from a mixed drink after it has been shaken or stirred and while it is being poured into the glass it will be served in. Strainers are used to cover the mouth of the glass a drink was stirred in or part of the cocktail shaker that it was shaken in. They have holes or slits small enough that only liquid can be poured out.
There are two main types of strainers. The Hawthorn strainer is flat and circular with a handle and several flat stabilizing prongs coming out of the rim. It has a metal spring around its rim that will roll inward slightly to fit inside a glass. The circular rim of the strainer need not be touching the rim of the glass, as the spring inside will filter out the ice.
The Julep strainer is concave and circular with a handle, and will fit tightly into a mixing glass when on an angle. The concave part of the strainer is perforated with several dozen small holes.