Genuine Charles Tyrwhitt brass collar stiffeners.  Price is for a pair.

Choose your length - 66mm for classic collars, or 55mm for cutaway collars.

These are available as both brand new (unused), or with a vintage patina (while stocks last) - see photos for reference, and choose your preferred option.

Description from Charles Tyrwhitt: These collar stiffeners for your Tyrwhitt shirts will keep your collar in place and prevent it from curling. Made from our classic brass, embossed with the Charles Tyrwhitt logo, and designed for classic or cutaway collars, they can be slipped in to ensure a straight, formal look to your shirt all day.

Also available are light flexible plastic stiffeners in 55mm for cutaway collars.

Multi-buy discount available, and combined postage for all purchases.  Returns accepted.  Best value new collar stiffeners on eBay.