Stab vest A stab vest , or stab proof vest is a reinforced piece of body armor , worn under or over other items of clothing , which is designed to resist knife attacks to the chest , back and sides . Stab vests are different from bulletproof vests , most of which offer protection against firearms but afford little against stabbing with sharp - tipped objects such as knives ; most stab vests afford less protection against bullets , particularly those of high caliber , but are designed to prevent serious injury by prohibiting knife penetration beyond a few millimeters . Stab vests are also needle and slash proof . Standards . " Ice pick " tests . In the mid - 1980s the state of California Department of Corrections issued a requirement for a body armor using a commercial ice pick as the test penetrator . The test method attempted to simulate the capacity of a human attacker to deliver impact energy with their upper body . As was later shown this test over stated the capacity of human attackers . The test used a drop mass or sabot that carried the ice pick . Using gravitational force , the height of the drop mass above the vest was proportional to the impact energy . This test specified 109 joules ( 81 ft · lbf ) of energy and a 7 . 3 kg ( 16 lb ) drop mass with a drop height of 153 cm ( 60 in ) and an ice pick with a 4 mm ( 0 . 16 in ) diameter with a sharp tip with a 5 . 4 m / s ( 17 ft / s ) terminal velocity in the test . The California standard did not include knife or cutting edge weapons in the test protocol . In this early phase only titanium and steel plate offerings were successful in addressing this requirement . It should be noted that these textile materials do not have equal performance with cutting - edge threats and these certifications were only with ice pick and were not tested with knives . UK . The PSDB work studied what kind of weapons are commonly used in stabbing attacks and what levels of impact energy fit young men are capable of generating during an attack . The study resulted in minimum performance ratings for armor used in the UK , as defined under PSDB publication 6 / 99 . The PSDB standard was replaced in 2007 with the current Home Office Scientific Development Branch ( HOSDB ) publication No . 39 / 07 / C which governs stab resistant body armor performance in the UK . This updated standard introduced a more stringent testing procedure with more drops than the previous standard plus the introduction of the P1 / B Blade which is found to be more aggressive that the older P1 / A Blade . In the UK there are no standalone ratings for spike resistance . For stab resistant armor to carry a spike resistance ( SP ) rating in the UK , it must first pass minimum knife resistance ( KR ) performance tests . US . In the US , the National Institute of Justice ( NIJ ) has established a stab resistant body armor test standard ( NIJ STD 0115 . 00 ) , based on the work in the UK , which defines two threat types : spike and edged blade . Manufacturers of body armor can voluntarily submit armor models for compliance testing through the National Law Enforcement and Corrections Technology Center in Rockville , MD . Through the program , manufacturers certify that their armor will defeat the specified threat at one of three threat levels . Threat levels 1 , 2 and 3 are based on impact energies of 24 - , 33 - and 43 - joules respectively . Use . Stab proof vests are commonly used by police in both the United Kingdom and New Zealand ; in both countries it is standard issue to every officer . They are also often worn by paramedics , security staff , traffic wardens , environmental wardens , customs officers , immigration officers , bailiffs , cash in transit officers , door supervisors / bouncers , or anyone who may be under any threat . Concealable Stab - Protective Body Armor . The Concealable Stab - Protective Body Armor ( CSPBA ) is a stab vest , worn by United States Army personnel performing law enforcement operations , including confinement of enemy prisoners of war and overseeing civilian internees , for protection against homemade weapons and handguns . The CSPBA provides soft armor protection to the torso against a 9mm , full metal jacket 124 - grain bullet and meets the California Ice Pick standard for protection against other crude stab / slash weapons . " This article incorporates work from https : / / peosoldier . army . mil / newpeo / Equipment / Temp . asp ? id = SPE _ CSPBA , which is in the public domain as it is a work of the United States Military . "