This listing is for one strap with snaps that can be used with any bowtie or necktie in the shop.
Straps are all one size. It is 14" long with 3" of velcro on each size, adjusting from about 9" to 13" and should fit from about 6 months to 12 years. Please measure your son's neck to be sure it will fit.
Tip: If you don't have a soft measuring tape, you can mark a string or ribbon and hold it against a ruler/tape measure.
Straps only come in a handful of solid colors so that they can be used with many different Cuddle Sleep Dream ties. The strap is not likely to be visible under a collared shirt.