I don't know anything about the history of this knife. Very similar to Aleutian Island Pete's work.
Brass finger guard, aluminum center spacer, aluminum pommel. It looks like the spacers are some kind of Formica or similar composite material. Blade length(tip of blade to finger guard): 7-5/8.
The item "WWII WW2 Custom OOAK Hand Made Theater Trench Combat Fighting Dagger Knife" is in sale since Thursday, January 16, 2020. This item is in the category "Collectibles\Militaria\WW II (1939-45)\Original Period Items\United States\Edged Weapons". The seller is "prettyimpracticals" and is located in Perkiomenville, Pennsylvania. This item can be shipped to United States.