The "Stallona" combat knife is a melee weapon in Fallout and Fallout 2.
The combat knife is a bladed weapon meant for survival and combat purposes. Unlike the knife, this weapon is made for fighting. It does a decent amount of damage early on and is useful when needing to slice multiple times per attack.
The name of the combat knife in the description of Fallout, Fallout 2 and Fallout Tactics is a reference to Sylvester Stallone in the Rambo series, where he plays an army veteran using a combat knife as a main weapon.