Vintage Brazilian M3 knife, possibly from the 1980's or 1990's, and made by military manufacturer Imbel
Specs:
Overall length: 28,5 cm
Blade length: 17,5 cm
Blade thickness: 4,9 mm
Blade steel: unknown (possibly polished 1070 steel)
Handle material: Black Bakelite
Guard: steel
Weight (knife only): 179 grams
Sheath: Leather