The Mark 81 is a general-purpose 250-pound (110 kg) bomb (nicknamed “Firecracker”). It's the smallest of the Mark 80 series of low-drag general-purpose bombs.

Developed for United States military forces in the 1950s, it was first used during the Vietnam War. The bomb consists of a forged steel case with 96 pounds (44 kg) of Composition H6, Minol or Tritonal explosive. The power of the Mk 81 was found to be inadequate for U.S. military tactical use, and it was quickly discontinued, although license-built copies or duplicates of this weapon remain in service with various other nations.

Development of a precision guided variant of the Mk 81 bomb (GBU-29) was started due to its potential to reduce collateral damage compared to larger bombs, but this program has now been cancelled in favor of the Small Diameter Bomb.

In low-level bombing, it is possible for the delivering aircraft to sustain damage from the blast and fragmentation effects of its own munitions since the aircraft and ordnance arrive at the target almost simultaneously. To address this issue, the standard Mk81 and 82 General-Purpose bombs can be fitted with a special high-drag tail fin unit. In this configuration, it is referred to as the Mk8x Snake Eye. The tail unit has four folded fins that spring open into a cruciform shape when the bomb is released, slowing the bomb by increasing drag, thus allowing the delivery aircraft to safely pass over the target before the bomb hits it.