The "Grenade, Hand, Anti-Tank No. 74", commonly known as the S.T. grenade or sticky bomb, was a British hand grenade designed and produced during the Second World War. The grenade was one of a number of ad hoc anti-tank weapons developed for use by the British Army and Home Guard after the loss of many anti-tank guns in France after the Dunkirk evacuation.
Designed by a team from MIR including Major Millis Jefferis and Stuart Macrae, the grenade consisted of a glass sphere containing an explosive made of nitroglycerin and additives which added stability to the mixture and gave it a squash-head-like effect, where the explosive deformed and spread out on the target before exploding. The detonation would be concentrated on a small area, rupturing a thicker armour plate than a more diffuse explosion. The charge was covered in a strong adhesive and surrounded by a sheet-metal casing. When the user pulled a pin on the handle of the grenade, the casing would fall away and expose the sticky sphere. Pulling another pin would arm the firing mechanism and the user would then attempt to attach the grenade to an enemy tank or other vehicle.