The interceptor body armor system consists of an Outer Tactical Vest (OTV) and two Small Arms Protective Inserts (SAPI). The OTV is lined with finely woven Kevlar KM2 aramid. The vest tested to stop 9mm 124 GR FMJ at 1,400 fps (426 mps) with minimal back face deformation and has a V-50 of 1525 fps. (Technically can't be called a Level III-A vest as the mil-spec does not call for testing with .44 Magnums, but the 9mm test is identical to NIJ Level III-A certified vest). The vest will also stop other slower moving fragments, and is also equipped with removable neck, throat, and shoulder and groin protection.

Two Small Arms Protective Inserts (SAPI) may also be added to the front and back of the vest, with each plate designed to stop up to three 7.62x51mm NATO rounds (also known as USA M80 .308 cal) with a muzzle velocity of 2,750 feet per second (838 m/s). The plates are the most technically advanced body armor fielded by the U.S. military, and are constructed of boron carbide ceramics with a Spectra-Dyneema shield backing that breaks down projectiles and halts their momentum before reaching the wearer.

The Interceptor armor also has attachment loops on the front of the vest which accommodate the same type of pockets used in the Modular Lightweight Load-carrying Equipment MOLLE backpack/carry vest system. This allows a soldier to tailor-fit his MOLLE and body armor system to meet mission needs. While not specifically designed for it, the loops can also easily attach All-purpose Lightweight Individual Carrying Equipment ALICE-based equipment, MOLLE's predecessor, as well as many pieces of civilian-made tactical gear.

The Interceptor Body Armor system weighs a total of 16.4 pounds (7.4 kg), with the vest weighing 8.4 pounds (3.8 kg), and two plates inserted weighing four pounds (1.8 kg) each. This is considerably lighter than the previous body armor fielded in Somalia weighing 25.1 pounds (11.4 kg) that most troops complained was too heavy and unwieldy for combat operations.

Side-SAPIs (SAPI is short for Small Arms Protection Insert) are also available, along with the newer version of the vital plate, the E-SAPI (Enhanced SAPI). These two systems are becoming standard for forward deployed troops in OEF and OIF III. The E-SAPI plates are thicker and heavier than the normal SAPIs, but they offer increased protection from M-80 AP ammunition. The Side-SAPIs protect the side of the torso under the arm. With the Interceptor body armor, E-SAPI plates, S-SAPI plates, and with the neck, throat and groin protectors installed the armor is significantly heavier than 16.4 pounds. A combat load of ammunition and first aid kit are almost universally attached to the webbing on the vest, adding even more mass.

The armor vest of the average US troop in Iraq weighs over 35 pounds, sometimes the vest with all their gear attached can weigh upwards of 45 pounds. There is a constant tradeoff, loss of mobility and comfort and more weight to carry versus increased protection. This is a point of contention in the US armed forces, with some favoring mobility, and others wanting as much protection as is practical.

The plates come in five different sizes and go into the front and back of the vest. The vest also has a quick-release feature in which a quick tug would drop the plates off the vest.