This bayonet was designed to fit the Finnish Model 1927, 1928, and 1928/30 Infantry Rifles and other variants that accept the knife bayonet (in lieu of the standard socket bayonet).
This bayonet is only a slight alteration from the Finnish Model 1927 in that the grips are fastened by two hollow rivets as opposed to solid rivets (there is little difference physically, externally). These bayonets are well made. The grips are wood; pommel employs a typical "bird's-head" style; slightly curved lower quillon without proper finial. It can be distinguished from the Model 1935 (aka 28/30 Civil Guard) as the 1927/28 does not employ an oil hole in the pommel.
This particular is stamped HACKMAN & Co on the blade ricasso.

Scabbards are blued sheet-rolled-steel; tear-drop finial. Two scabbards types are known - 2nd type shown; the 1st type had two vertical flutes (grooves) stamped into the sides.