Stonefish is a naval influence mine manufactured by British defence company BAE Systems.
[1] There has been conjecture that South Africa, Chile, Iraq, Libya and possibly other countries may have gained access to either some early Stonefish information or to similar technology.
It is a cylindrically shaped, modular weapon, comprising three separate sections which are joined together to form one unit: There are four different versions of the Stonefish mine, only one of which is intended for use in combat.
The physical measurements of a Stonefish mine are such that it can easily be loaded into the torpedo tubes of submarines, then deployed using a small charge of compressed air to expel it.
The DSP circuitry includes such features as the ability to set thresholds regarding the signal strength and adjust sterilisation delay times (how long before the mine renders itself inoperative).