It was built on the "Panzerkampfwagen" 38(t)'s widened and lengthened chassis with modified suspension (larger road-wheels from the Praga TNH n.A prototype reconnaissance tank) and up-rated engine. The new engine was 160 PS Praga AC/2 6-cylinder engine coupled to a Praga-Wilson gearbox (5 forward and 1 reverse gear). The chassis was modified in order to accommodate a larger gun and thicker armour than the regular "Panzerkampfwagen" 38(t) tank. Its combat weight was 16 metric tons (versus 9.8-tonnes for the Pz 38(t)) and it could travel at a maximum speed of 42 km/h.