These stiffeners are used to stop collars 'curling'. Shirts usually come with a plastic insert, which after several washes tend to become weaker and this causes the collar to become out of shape. An excellent idea is to have these engraved with the initials of the lucky man. 57mm x 10mm. These stiffeners will fit all shirts. A good fit for Thomas Pink and slightly firmer fit for TM Lewin.