This is a Green Stuff World Hobby Razor Saw

A single-edged hobby saw is a handy tool for precise detail crosscutting on a variety of materials such as plastics, resins, soft metals, balsa woods, and fiberglass.

This superfine saw is mostly used for conversions or building, but also for cutting through miniature parts too thick for the Sider Cutters.

Blade Length: 115mm (4.5inches)
Blade Width:  15,87 mm (5/8 inches)
Overall length: 200mm (7.80inches)
Blade teeth: 180 teeth for clean cuts
Blade Thickness: 0.2mm (0.008inches)