The Soviet PSO-1 (Pritsel Snaipersky Optichesky, "Optical Sniper Sight") telescopic sight was, at the time of its introduction (around 1964), the most technically advanced telescopic sight ever designed for a mass-production designated marksman or sniper rifle.
The PSO-1 telescopic sight is manufactured in Russia by the Novosibirsk instrument-making factory (NPZ Optics State Plant) and is issued with the Russian military SVD sniper rifle.
The PSO-1 SVD and PSO-1 Simonov are available weapon attachments that both provide 1.95x zoom magnification. This scope offers lower magnification than the standard sniper scope, but does provide peripheral vision.
— Battlelog description
The PSO-1 is a weapon attachment featured in Battlefield 3 that provides 4× (346%) magnification. Unlike the sniper's default PKS-07 scope, the player will not suffer from scope glint. It cannot be mounted to PDWs, besides the AS VAL, due to complications with the amount of space available on most PDW attachment rails, but it can be mounted to all other types of primary weapons in game. The PSO-1 is a very obtrusive sight, coupled with its small sight aperture which blocks much of the peripheral vision, the PSO-1 can be less useful than the ACOG due to these disadvantages. However, unlike the ACOG, the PSO-1 does not have a vertical line down from the aimpoint, making it easier to gauge the trajectory and make correcting shots during long range shooting.
The PSO-1 features a stadiametric rangefinder in the lower-left side of the reticle, but it is not accurate in-game.
— Battlelog description
The PSO-1, along with the other two 4x scopes, only appear attached to Designated Marksman Rifles. The PSO-1 only appears attached to the SVD-12. The PSO-1 is a very obtrusive sight, coupled with its small sight aperture which blocks much of the peripheral vision, the PSO-1 can be less useful than the ACOG due to these disadvantages.
The PSO-1 is unlocked for Russian primary weapons through progression and is unlocked through Battlepacks for all other primary weapons. It is the first optic unlocked for Russian DMRs, requiring only ten kills.
— Battlelog Description
The PSO-1 (4x) is an attachment featured in Battlefield Hardline. Functioning similar to the Battlefield 4 variant, it increases a weapons magnification by 4x.