This flask is amazing! It is hallmarked for London, England, 1916. The mark that some would call a makers mark, could also be a sponsors mark.  The mark appears to be that of Charles and George Nicolet who were primarily importers of watches from Switzerland to England. Whatever the case, the piece is outstanding in its design. The screw-top cap is sterling and hallmarked, as is the removable cup which retains much of its interior gilt. The cap hallmark is faint, and the cup hallmark is very clear. The glass is fluted. The flask measures 5 3/4" tall, 2 3/4 - 3" across and about 1 1/2" wide. It is in superb condition and would be an outstanding addition to your collection or to that of someone special.