Base
Steuler produced with a reddish clay up until the early 1960s and then switched to a white clay from the 1960s onwards. This switch was possibly because they were starting to gear up for mass production techniques.

Between 1933 and around 1959/60 Steuler used the marks shown below and mainly red clay. Sizes in this period were typically marked with a number 0, 1, 2 ect. Form numbers tended to be in the 4000 range.

The Steuler mark below was introduced in around 1959/60 and at a similar time Stuler transitioned to white clay and marking the height in cm. Form numbers tended to be in the 0-600 range.

Some earlier items used only numbers without any company symbol.

Stickers/Labels
Steuler items are only very occasionally found with a company label.