The SUSAT (Sight Unit Small Arms, Trilux) scope is a scope with x4 magnification with tritium-powered illumination developed by Royal Armaments Research Development Establishment (RARDE) based in England. The scope is found in a variety of locations from vendors, to stashes, and/or some stalkers who mount it on their weapons. It can only be mounted on weapons with a Picatinny rail - more specifically, NATO-class weaponry. Despite the x4 magnification on a real SUSAT scope, the ones in the S.T.A.L.K.E.R. games never magnify more than x2, except the integrated one on the Gauss Rifle.
The SUSAT Scope can be mounted to NATO weapons in all three S.T.A.L.K.E.R. games. In Clear Sky and Call of Pripyat, you may have to apply upgrades in order to mount the scope.
The SUSAT is comparatively more common than its Warsaw counterpart, the PSO-1. Nearly every Mercenary encountered throughout the series has a SUSAT attached to their rifle, and most Freedom members with LR-300s have them as well.
A great many scopes will be found later in the game in the Wild Territory near the construction site. Initially however, the Mercs are not equipped with them until at least the second visit there.
Some stashes in the Wild Territory contain the scope, notably:
Nearly every Merc encountered in Call of Pripyat has a standard x4 SUSAT attached to their rifles, giving the player an ample supply of them right from the very first level. Most Stalkers, not just Freedomers, will attach SUSATs to their own weapons as well. Like the PSO-1, Call of Pripyat introduces several variations that can be bought from traders or found in stashes. Most interestingly, the SUSAT can be attached to the Protecta shotgun, the only shotgun capable of taking any kind of attachment.
Scope Variants
x4 SUSAT Scope - The scope from Clear Sky. Very common, as it is the only version other Stalkers and Mercs make use of. The lens portion is colored blue in the inventory for easy identification. Despite its 4x label, its magnification is only 2x.
x1.6 SUSAT Scope - For close to medium range combat. The 'classic' scope from Shadow of Chernobyl that is built for CQB weapons. Lower resolution, but quicker turning when scoped in. Only a strip of the lens is colored blue.
x4 SUSAT Night Scope - A standard x4 scope with third-generation night-vision. The scope is rather rare - Owl may sell them after doing his missions and from Hawaiian after partially assisting Freedom. Despite its 4x label, its magnification is only 2x. The lens portion is colored green.
x1.6 SUSAT Twilight Scope - A standard x4 scope with a special tinted lens, which increases the image contrast - making it more useful than night-vision scopes during the early morning and late night. Poor visibility in pure darkness. Sometimes the lens, due to a glitch may appear green in inventory, like the NVG, whereas it should be yellow. Despite its 4x label, its magnification is only 1.6x. If you sight in through a Twilight scope with NV modded armor or headgear, your NV will be inactive while sighted in, because they share the same property. This is preferable for rail system weapons whose scopes can be easily swapped, however if you've modded an F2000 or G36 with a Dusk scope you can no longer sight in with NV which is, as you may have guessed, a problem in dark areas.
SUSAT Mera Scope - An adjustable scope, can be adjusted all the way from x1.6-x2, even though the game claims it is a x1.6-x4 scope. The scope can be adjusted using your mouse's scroll wheel. Both ends of the SUSAT are colored blue in the inventory for identification. This scope is only sold by Hawaiian after attaining the Friend of Freedom achievement.
Trivia
The L85A1 has a non-detachable SUSAT in all three S.T.A.L.K.E.R. games.
In Call of Pripyat, leaving a special SUSAT scope (Everything but the x4 variant) attached to a weapon, storing it in a stash and leaving the map area where the stash is, will cause it to revert back to the x4 variant. This can be avoided by simply removing the scope when storing the weapon. Storing special scopes separately won't bug it.
If one looks closely they can see the outline of a PSO.
