Here is a vintage Spirella corset dating from later teens or early 1920s.  This corset is a modeling / fitting garment which was used only as a sample for fitting woman for a custom made corset.  The corset is an expandable size to fit women, both large and small.    Printed cloth label on the corset gives the patent # 1,928,101, plus trademark Spirella.  Label also has an L (possibly for large?)  Made of cotton in a lovely soft shade of peach pink.
It is complete with the extension piece.

Spirella Corset Co was founded in 1904 in Meadville, Pa.  Over the next few years locations were expanded to the UK, Canada and Germany.  All corsets manufactured were made to fit each particular customer.  Women staff members, called corsetieres, were sent to a customer's home where she would fit the customer, with the modeling garment, to exact measurements for the custom order.

Length of the corset is 16" long in front and 14" in the back.  Fully extended size is 38" around or about, depending on how tightly the laces are drawn.  Minimum size would be about 30" to 32" around.  The condition of this corset is very nice.  Perhaps never used.  The laces appear never to have been untied.

The history of this company is very interesting.  What a great study piece!  Salesman's sample, if you will