Abstract: This bow constrictor allows a peep sight or other device to be easily served in to a bowstring or bow cable without the expense and time-consuming services of a professional. A user simply splits the bowstring strands then inserts the bowstring constrictor with an associated device, guiding the bowstring through the grooves of the constrictor. The grooves couple the constrictor tightly to the bowstring applying minimal stress with minimal resultant wear. The attachment mechanism may be incorporated as a single unit into peep sights, knotting devices, cable weights or other devices of use to an archer or bow hunter. An independent, standalone version may also be used to spread and then constrict cable strands to support other items. Though designed to meet the needs of an archer or bow hunter with regard to a bowstring or bow cable, the described mechanism is scalable for other uses as well.