The seal stamp (typar) is made of a copper alloy, most likely brass. With a height of 45 mm, it is one of the larger shield-shaped typars, which date from the 13th century. On the back, the broken-off part of what was probably originally a soldered, bar-shaped handle can be seen. The surrounding seal inscription reads "+ SIGILLUM WLVERI DE INSVLA" and can be read as "Seal of the Wulvers de Insula" or "Seal of the Wulfers of Werder". The Gothic majuscule font used is common in the 13th and 14th centuries. The simple, geometric coat of arms in the center of the typar consists of four intersecting diagonal lines and represents a shield decorated with diamonds, the original coat of arms of which certainly had contrasting color fields.