The BTR-D is a Soviet airborne multi-purpose tracked armoured personnel carrier which was introduced in 1974 and first seen by the West in 1979 during the Soviet–Afghan War. BTR-D stands for Bronetransportyor Desanta (БТР-Д, Бронетранспортер Десанта, literally “armoured transporter of the Airborne”).It is based on the BMD-1 airborne IFV. NATO gave it the designation BMD M1979. This vehicle is airdployable and is continued to be used today.
The Reostat was a BTR-D converted into an airborne artillery battalion fire direction vehicle. The vehicle is fitted with a turret equipped with NNP-21 and V-7 observation devices, three R-173 and R-159 radiosets, PAB-2AM aiming circle, three antennae mounts, DSP-30 and DAK-2 rangefinders. The turret was also equipped with PSNR-5K (1RL-133-1) “Tall Mike” ground surveillance radar mounted on the roof of the turret. Located over the turret front sights were the visors hinged in the cente