From the back of the module
Twilight: 2000 / Merc: 2000 Ref's Screen
The Twilight: 2000 Ref's Screen is fully usable with Twilight: 2000, Merc: 2000, and the other products in the Twilight: 2000 system. The screen itself contains the charts a referee needs most often in a conveniently arranged, stand up screen, to conceal the referee's secrets from the players.
The Twilight: 2000 Ref's Screen comes wrapped around a 16-page booklet containing new D20 game mechanics, consolidated small arms and heavy weapons listings (from both Small Arms of the World and Heavy Weapons Handbook). rules extensions to character generation, combat (including a system for skill-based fully automatic fire), still more charts (in a 4-page pull out section), and optional rules including (among other things) the first treatment of enhanced damage rounds (such as hollow point and mercury loads) in the Twilight: 2000 system.
The new D20 game mechanics expand the range of possible task results and increase the speed, simplicity and flexibility of the game system, at the same time bringing a greater sense of realism and enjoyment.