The old price is hand-written on the card: 3 1/2 d (thruppence halfpenny).
The card is marked IMITATION JEWELLERY MADE IN ENGLAND
The stays are made of a flexible plastic, and are quite large.
It is difficult to know where to measure them - in the position shown on the card, they measure 2" x 2 1/4" (6 cm x 5 cm).
Suitable for shirts or for semi-stiff collars.
I have included a picture of one of the stays in use, slotted into a Marcella collar.
These delightful little items are unsold shop stock - probably from the 1930s or thereabouts.
They have been carefully stored in the shop, and are perfectly fit for use.