12.8 cm Kanone 81(K-81/2) was a German heavy anti-tank gun designed to fight against heavy Soviet tanks like IS-2. The German army had encountered the Russian 122 mm guns and had issued a requirement for a similar weapon. Approximately 50 barrels and breeches were used on existing carriages. The weapon that used the ex-French GPF-T carriage was known as the K 81/1 while the K 81/2 used the ex-Russian A-19/ML-20 carriages with shield and balancing gear removed. the cradle and recoil system were discarded and the 128mm gun was mounted in a ring cradle similar to that used on the 81/1. Another version K 81/2 was also built, in which original Russian equilibrators were retained.