The Weyland-Yutani 88 Mod 4 Combat Pistol, also known simply as the Combat Pistol, is an 18-round, blowback-operated, striker-fired, double action only, semi-automatic pistol chambered in 9×19mm Parabellum. Made completely of nano-bound hard impact plastic and other synthetic materials, its design was nearly identical to that of the Heckler & Koch VP70, a pistol in service at approximately the same time as the 88 Mode 4.
The 88 Mod 4 uses a spring-loaded striker instead of a conventional firing pin. It is double action only so the trigger pull is relatively heavy. In lieu of a blade front sight, the 88 Mod 4 uses a polished ramp with a central notch in the middle to provide the illusion of a dark front post. The 88 Mod 4 uses a manual safety and is the circular button located immediately behind the trigger and is a crossblock safety.
- C43 Extended Magazine: "Large capacity pistol magazine created from lightweight plastics; lightweight composition allows each magazine to hold more ammunition without adding significant weight."
- S91 Dot Reflex Sight: "Non-magnifying reflector sight outfitted with a red LED dot; LED dot remains consistently positioned, allowing for faster target acquisition."
- Full-Auto Action Replacement: "Heavily modified firing mechanisms throughout the 88 Mod 4 allow conversion from semi-automatic to fully-automatic fire."
- The 88 Mod 4 is visually based on the Heckler & Koch VP70, which served as the USCM's standard issue sidearm in Aliens.
- The slide of the 88 Mod 4 Combat Pistol reads "MK 88 Mod 4".
- The legendary weapon Gorman's Pistol (which is actually a VP70) is a modified 88 Mod 4 model, as the slide of Gorman's Pistol still reads "MK 88 Mod 4".
- In-game "Mod" and "4" are not separated when the pistol's name is in all capitals.
- In the Brady Games Aliens: Colonial Marines Guide, the 88 Mod 4 is the only weapon whose title is not in bold.
- Also in the Brady Games guide, despite it being referred to as the "88 Mod 4" in Firing Range (the 88 Mod 4 displayed in the locker) in the Full-Auto Action Replacement description in-game, the guide refers to it as the "88 MOD4".
- The 88 Mod 4 pistol is fitted with what appears to be an underbarrel accessory rail, despite the fact it cannot be fitted with any underbarrel attachments in the game.