During WW2 2 inch mortar tail units came in 3 types,The first made of an aluminium-silicon alloy,these were replaced as they were vulnarable to breaking upon launching.The next were made of Mazak,but these too were fragile and prone to breaking especially at extreme low temperatures.The final type was made of steel and entered service in 1944 and remained in use untill the 2 in mortar was withdrawn from service,the following pictures show various marks of 2 in tail fin units
