An Antique Durham Duplex Razor, a type of straight safety razor.

Here's more information about this historical shaving tool:

Designed for Safety: Unlike traditional cut-throat straight razors, the Durham Duplex razor featured a safety comb, which was intended to make shaving safer and prevent nicks and cuts.

Proprietary Blades: These razors used proprietary double-edged steel blades designed specifically for the Durham Duplex system, offering a way to re-sharpen and reuse blades.

Historical Significance: The Durham Duplex Razor Company Inc. was founded in New York in 1875, and the razor system, including its unique slotted blade, was considered a significant technological advancement in shaving during the late 19th and mid-20th centuries.

Collectibility: Vintage Durham Duplex razors, especially those with original cases or in good condition, are sought after by collectors of antique shaving tools and barber shop memorabilia.

Modern Use Considerations: While historically innovative, finding suitable new blades for the Durham Duplex can be challenging, as modern blades like "carpet cutters" or "dog dresser" blades are often not truly suitable or safe for facial shaving, according to some enthusiasts.