"Ewww, their commander picks his nose during the briefing."
Binoculars is high-tier Scout-exclusive unlockable Equipment which can be used in one of three equipment slots available per Trooper. Trooper can use binoculars two times per one battle. Upon use it forces the enemy to deploy one extra trooper immediately, the trooper receives a penalty of -400 Initiative. This penalty essentially makes the new trooper a sitting duck to shoot at. Upon occasion, binoculars might force an allied Spy to deploy into the enemy's side of the field, in such case they are penalized as well.
The deployment penalty is of such size that it will negate all other initiative boosts available to the enemy trooper at the start (such as On point). A spy would need to be at least level 40 to be able to withstand the effect of this item (which is only a possibility in a Raid).
Comparing to the Glue Grenade (-200 IP) binoculars effect is twice as powerful. Binoculars may not be an Area of Effect, like the Glue Grenade, but it may be used up to two times in the same battle (sometimes consecutively).
The penalized trooper may still use a Motorcycle (in which case he will be forced to wait at the edge of the screen until his turn comes up, potentially destroying the bike if he's shot upon).
Binoculars can make life easier while facing smaller waves of enemies or with explosives at your disposal. Just make sure you've got enough materiel to face bigger amounts of hostile dummies without losing combat effectiveness, as an extra target can draw a portion of your grunts' attention. If you are lacking armaments you might waste the moment, allowing the newly deployed trooper to recovere and join the combat against you.