Press Button Knife Co INVINCIBLE antique switchblade nice blade

Vintage Press Button Knife Co INVINCIBLE model switchblade made in Walden, NY sometime between 1912 and 1923. The knife measures 4 7/8 inches closed and 8 5/8 inches open steel liners. The blade is marked PRESS BUTTON KNIFE CO WALDEN, NY on the tang and the backside is blank. The blade is mostly full with heavy patina, light scratches, light pitting and spotting, but overall good blade. The jigged bone scales are in very good condition with no cracks.  The knife functions well with the blade tip below the liners closed, opens strong when button pressed and locks open with some up and down and side to side movement at the tip. Average lockup for these old knives and rattles if shaken when open. About 1/8" up and down and little side to side. This is a nice working example of a 100+ year old American made switchblade. VG+ condition.