M090607a
Circle containing a crowned initial "W" above "BAVARIA".
It is often claimed that this mark was used by one of the many Gebrüder Winterling factories. No further insight or proof was provided; the closest I could find was a basic similarity in the marks used by the company of Heinrich Winterling. However, this was neither confirmed nor denied when I contacted them shortly before their closure.
M090607a
Circle containing a crowned initial "W" above "BAVARIA".
M090607b
All examples found were relatively constant in colour and always red.