"Tiger I heavy tank originally received the designation of Panzerkampfwagen VI H (8.8 cm) Ausf H1 - Sd.Kfz.182, but then in March 1943, was redesignated to Panzerkampfwagen Tiger (8.8 cm L/56) Ausf E - Sd.Kfz.181. It was commonly referred to as Tiger, Tiger I and PzKpfw VI. Officially there was only type of Tiger tank produced, but during the duration of production improvements were carried on." Wikipedia