Press Button Knife Co #1000 INVINCIBLE antique switchblade knife

Antique Press Button Knife Co INVINCIBLE model #1000 switchblade made in Walden, NY sometime between 1912 and 1923. The knife measures 4 7/8 inches closed and 8 1/2 inches open with steel liners and nickel silver bolsters & button. The clip blade is about 1/4 inch short and 93% full, or better with some light scratches and the tang is clearly stamped PRESS BUTTON KNIFE CO WALDEN, NY and the backside is blank. The picked bone scales are in very good condition with no cracks, but the bolsters are scuffed up a bit from use. The knife functions well with the blade tip well below the liners closed, opens strong when button pressed and locks open with less than 1/16" movement at the tip open. It barely rattles if shaken with the blade open as most of these do. This is a nice working example of a 100+ year old American made switchblade. VG+ condition.