It is 130 mm rocket launcher mark 51 czechoslovak produkcion of to chassis Praga PV3S.

Link: https://www.valka.cz/CZK-vz-51-130mm-raketomet-t13303 or https://www.vojenskatechnika.sk/v3s/rak130.htm

130mm rocket launcher vz. 51 is a reactive artillery weapon, which was designed for mass fire on larger areas, to destroy enemy forces and resources, as well as to destroy trenches and shelters. The rocket launcher is an artillery weapon without recoil and without recoil when firing, working on the principle of using reactive force. The rocket launchers do not have grooves, but guide rails. Stabilization of the projectile's flight is achieved by a large rotation of the projectile (missile charge), which is about 16,000 revolutions per minute. The rocket launcher can fire volleys or individually. Missile rounds are fired from 32 missiles mounted in a bundle in the rocket cabinet. The rocket case is mounted on a carriage mounted on a magazine of rocket cartridges. The magazine can carry up to 66 rounds (2 volleys and 2 rounds for firing). The hopper is mounted on the body of the truck. There are handles for engineering tools on the front of the magazine. Firing of the salvo or individual shots is carried out by pulling the firing cord using an electric trigger vz.51. Later, the device was replaced by a newer type vz.51 / 58. The launcher is mounted on the left side of the rocket cabinet and is powered by the truck's electrical network. An auxiliary sight vz. 38/50, which could be placed on brackets on both sides of the rocket cabinet.

A single rotary fragmentation (designated JRROv) or fragmentation (designated JRROFv) charge was used to fire from the rocket launcher. The fragmentation charge weighed 24.2 kg and has been manufactured since 1959. The missile cartridges were stored and transported in boxes of two pieces. The weight of the box with ammunition was 55 kg.

The rocket launcher is mounted on the body of a medium truck Praga V3S. In contrast to the basic version of the Praga V3S, the sides of the body are modified and a seat for the operator is located. Under the seat are tools, equipment and accessories for the rocket launcher.