Flylock Small Silver double switchblade vintage knife w/shackle & file blade

Antique Flylock Small Silver colored double switchblade vintage knife w/shackle & file blade made 1920s by Flylock Knife Co a division of Challenge Cutlery Corp of Bridgeport, CT. The knife measures 2 7/8 inches closed and 5 13/16 inches with both blades open and has brass liners and lanyard ring. It's a spear/file blade combo with both blades showing age and use. The spear blade is about 94% full and dark with patina and spotting and is stamped Flyock REG US PAT on the front and FLYLOCK KNIFE CO B'PORT CT on the reverse. The small file blade is very uncommon with same stamp on the front as the spear point blade and reverse is US PAT 3-5-18. The scales are stamped brass with silver coating, much of which has worn off from use/carry, but are in good condition and looks like maybe E.B initials inscribed. The knife works well with both blade tips inside the liners closed, open fairly well with no kickback and average lockup open. Good condition.