The French-Epstein device is an item in System Shock 2. The French-Epstein device can modify any weapon, except one that has already been modified fully, regardless of the Soldier's Modify skill. It is rare, and is exhausted after a single use.
The French-Epstein device uses Nanites to analyze and modify any weapon.
The French-Epstein is one of the most valuable tools available in the game, due both to its rarity and utility. Each modification to a weapon guarantees a 15% damage buff, along with a statistical bonus that is unique to each weapon. The only weapons that cannot be upgraded are melee weapons like the Wrench and the Crystal Shard, and weapons that have already been upgraded twice.
The French-Epstein device incurs no nanite cost, unlike using the Modify skill.
There are enough French-Epstein devices in the game for the Soldier to fully modify three weapons, except on Impossible difficulty. However, they are easy to waste, especially if the Soldier doesn't have Maintenance or Repair. If the player is careful, they can max out their chosen weapons without putting any points into Modify.
- Deck 1 Sector B: cargo bay 2B, far end (rightmost in the map), third floor
- Deck 3 Sector D: Hackable crate in a small room, opposite the only replicator in the level (not present on Impossible difficulty.)
- Deck 4 Sector B: Crew room.
- Deck 4 Sector D: By the Interpolating Simulation Unit (not present on Impossible difficulty.)
- Deck 6 Sector B: In the escape pod area, lying on the ground.
- Deck 6 Sector A: Near the working shuttle bay shield control console, beside the window.
- Rickenbacker Pod 1: From the Chemical Storeroom, follow the Nacelle B floor signs until you see a Viral Proliferator on the floor. At the end of the corridor, there's a Blast Turret. Down the hall and to the left is a room with a window to space and a Rickenbacker Turret. In that room, there's French-Epstein device lying on the floor.