cane handle (approximately 16 inches or 40 cm) allowed the user to throw the grenade farther than the blast of the explosion. Early in World War I, combatant nations only had small grenades, similar to Hales' and Aasen's design. The Italian Besozzi grenade had a five-second fuze with a match-tip that was ignited by striking on a ring on the soldier's hand. As an interim measure, troops often improvised their own grenades, such as the jam tin grenade. Fragmentation grenade Improvised grenades were replaced when manufactured versions became available. The first modern fragmentation grenade was the Mills bomb, which became available to British front-line troops in 1915. William Mills, a hand grenade designer from Sunderland, patented, developed and manufactured the "Mills bomb" at the Mills Munition Factory in Birmingham, England in 1915, designating it the No. 5. It was described as the first "safe grenade". They were explosive-filled steel canisters with a triggering pin and a distinctive deeply notched exterior surface. This segmentation was thought to aid fragmentation and increase the grenade's deadliness, but later research showed that it did not improve fragmentation. Improved fragmentation designs were later made with the notches on the inside, but at that time they would have been too expensive to produce. The external segmentation of the original Mills bomb was retained, as it provided a positive grip surface. This basic "pin-and-pineapple" design is still used in some modern grenades. The Mills bomb underwent numerous modifications. The No. 23 was a variant of the No. 5 with a rodded base plug which allowed it to be fired from a rifle. This concept evolved further with the No. 36, a variant with a detachable base plate to allow use with a rifle discharger cup. The final variation of the Mills bomb, the No. 36M, was specially designed and waterproofed with shellac for use initially in the hot climate of Mesopotamia in 1917, and remained in production for many years. By 1918, the No. 5 and No. 23 were declared obsolete and the No. 36 (but not the 36M) followed in 1932. The Mills had a grooved cast iron "pineapple" with a central striker held by a close hand lever and secured with a pin. A competent thrower could manage with reasonable accuracy, but the grenade could throw lethal fragments farther than this; after throwing, the user had to take cover immediately. The British Home Guard was instructed that the throwing range of the No. 36 was about with a danger area of about . Approximately 75,000,000 grenades were manufactured during World War I, used in the war and remaining in use through to the Second World War. At first, the grenade was fitted with a seven-second fuze, but during combat in the Battle of France in 1940, this delay proved too long, giving defenders time to escape the explosion or to throw the grenade back, so the delay was reduced to four seconds. The F1 grenade was first produced in limited quantities by France in May 1915. This new weapon had improvements from the experience of the first months of the war: the shape was more modern, with an external groove pattern for better grip and easier fragmentation. The second expectation proved deceptive, as the explosion in practice gave no more than 10 fragments (although the pattern was designed to split into all the 38 drawn divisions). The design proved to be very functional, especially due to its stability compared to other grenades of the same period. The F1 was used by many foreign armies from 1915 to 1940. Stick grenade Stick grenades have a long