Puckerings has dated this piece to the 1940s.
The jug has a removable strainer which fixes into the top of the jug and the two mounts are used to twist and open this strainer; these also act as a lemon squeezer / reamer, pressing the fresh juice into the cocktail jug or pitcher, the strainer catching any pips.

The slot in the center is for the original cocktail spoon / server.
Excellent condition dating to c.1940 and spanning 7" spout to handle x 4 1/4" x 9 1/2" tall to top of spoon handle.
Item: 44104
FREE Worldwide Registered Airmail Directly From the UK
Puckerings has dated this piece to the 1940s.
A quality online collection of fine english antique smalls with free worldwide shipping from london, england
You can view the stock and full dealer information on the Puckerings Profile Page