The term "Mills Bomb" refers to a series of British hand grenades designed by William Mills, the first modern fragmentation grenades in the world, developed in 1915 and widely used in the First and Second World Wars. The weapon was also the first grenade with the familiar "pineapple" grooves on the casing. While these were at the time believed to aid in fragmentation, the original purpose, according to Mills' notes, was to make the grenade easier to grip. The grenade had a Baratol explosive filler which gave it a danger zone with a radius of up to 100 meters, making it a defensive grenade designed to be used from behind cover. The Mills bomb initially had a seven second fuse, but it was reduced to four seconds after this proved to be too long, allowing the enemy to escape the blast zone or even throw the grenade back.