An interesting vintage HELIX brass drawing compass.

Marked 'HELIX REGD MADE IN ENGLAND' on the locking wheel.

Complete with knurled handle or thumb grip with internal and external threads allowing it to also act as a point protector when not is use, please see images.

³/₈ inch (9mm) steel point.

A little over 4³/₈ inches (112mm) overall length from the top of the handle to the tip of the point.