These are removable adhesive tabs that attach to the inside of the collar. From there you can either glue the collar to the neckband or to the fabric covering the collarbone. Gluing to a collar is not suitable for a button down or similar shaped collar. Mainly due to the size of the collar, it doesn't fit naturally into the neckband. Please note that you cannot use them with a tie. I figured they would be useful for attaching the polo collar to the collarbone of a shirt. There are two problems here: it also looks unnatural, and the glue tabs don't stick well to the mesh material. The instructions warn you not to remove them before dry cleaning. The instructions don't say if they're safe to iron, but I wouldn't. It's expensive for a disposable product.
Stiffs Wurkin: Premium π Assorted Brass Collar for Polished Style
9 Review
π Premium Plastic Collar Stays - Assorted Sizes in Crisp White Finish
9 Review
Stainless Steel Collar Stays Shirts
9 Review
π Durable Plastic Collar Stays in a Range of Sizes: A Must-Have Wardrobe Accessory
8 Review