Blackjacks and saps were popular among law enforcement for a time due to their low profile, small size, and usability at very close range, such as when grappling with a suspect. Besides the head, they were also used on the elbows, wrists, shins, collarbone, and groin. The flat sap, in particular, could be used to strike large muscle groups with the edge. In the early days of use, they were favored for their ability to stun or knock a suspect unconscious with a blow to the head. By the late 1960s head-strikes with impact weapons in general were strongly discouraged by most police departments and trainers because of the risk of death or permanent injury, as well as its questionable effectiveness. By the 1990s virtually all modern police departments had phased them out from their issued equipment, and most banned their use entirely.