Already in the 14th century, this seal design was being used as a coat of arms and a banner.
These were incorporated into the seal design featuring a shield surmounted by a mitre after suggestions from the residents of the college.
The skippets themselves also were engraved with the seal design.
This is the earliest known full-color version of the seal design, and the artist is unknown.
O-rings are one of the simplest, yet most engineered, precise, and useful seal designs ever developed.
The current version dates from 1886, and is the third seal design used by the Senate since its inception in 1789.
Another failure mode is casing seal design.
The flap was secured with a large dribbling of amber wax impressed with a sheaf-of-wheat seal design.
Other internal 12A changes included moving from dual row side seals to single row and significant changes to apex seal design.
A different seal design for similar applications is a rotating face seal.