The Enhanced Instantaneous Smoke-Screening System EIS-917 has been developed by Israel Military Industries as a countermeasure to anti-tank guided missiles, laser homing munitions and other battlefield threats.

Protection is attained by the instantaneous generation of a large smoke screen, which lasts long enough to enable the target to manoeuvre out of the danger zone.

The system consists of a launcher and ammunition, designed and manufactured in a modular concept, making it possible to fit armoured fighting vehicles, transport vehicles and highly vulnerable stationary targets. The launch system and the smoke shell are designed to withstand hostile battlefield conditions, including hits by artillery shell fragments.

The basic system component of the EIS-917 is the barrel with a 73 mm diameter which is attached to the control housing. The number of barrels and the angle of the installation depend on the operational requirement. A typical example is that for a six-barrelled launcher.

Two IS-6 launchers, covered in detail in the following entry, are mounted on the forward part of the turret, one at each side of the gun. The fire-control unit is located inside the turret.

Each launcher consist of a six-tube cluster protected by 8 mm steel armour against artillery shell fragments. The launcher is equipped with an electromechanical dual-function selector switch which provides for the automatic selection of launch-tube firing sequence and short-circuit of shell-firing circuit until receipt of firing pulse from the fire-control unit.

The Smoke Shell M917 carries approximately 850 g of specially modified Red Phosphorous (RP) smoke-producing material.

The shell is loaded into the launcher. The electric primer is short-circuited by the internal electric circuitry. This short circuit is removed only when a firing pulse is applied. This pulse activates the electric primer, which in turn ignites the black powder in the booster cell.

The black powder in the booster cell propels the shell from the launcher and activates the delay unit. After a delay of 1.5 to 2 seconds, the delay unit ignites the black powder in the buster, creating high pressure and high temperature, thereby igniting the RP and bursting the plastic container. The RP particles are dispersed and rapidly form a smoke screen.

A smoke screen is created by launching a salvo of two or more specially designed smoke shells. An effective smoke screen develops within 2 seconds after firing. Under ordinary wind conditions, the smoke screen persists for 60 to 120 seconds.

The screen produced 60 to 70 m ahead of the tank is initially 60 m wide and 4 to 8 m high; it continues to expand over a broader front. The initial construction angle attained by firing two shells is about 70°. The direction of subsequent growth depends on prevailing wind conditions.

Production as required.