Wilk: Beginning in 1986, the Polish T-72 Wilk project was instituted to allow tank repair plants to upgrade T-72 tanks within their own facilities. In particular, it was proposed that the Soviet-made Volna fire control system be replaced by the Czechoslovak-made Kladivo FCS or by the Polish SKO-1 Mérida, which was originally designed for T-55AM "Merida". Besides the new FCS, the Radomka passive night vision devices were installed in the driver's compartment, as was the Liswarta night sight, Obra laser illumination warning system, Tellur anti-laser smoke grenade launchers, solid or modular metal side skirts and the Polish-developed Erawa-1 or Erawa-2 explosive reactive armour was also fitted.