The hełm wz.
 31 ("helmet, 1931 pattern") was the basic combat helmet of the Polish Army before the outbreak of World War II and during the Invasion of Poland.
 The helmet became the basic type of combat headgear for Polish military formations in 1930s and during the early stages of World War II.
 It was also exported to Persia, Albania and Republican Spain.
 By September 1939 approximately 320,000 copies were delivered to the Polish Army.
The Mk III Helmet was a steel military combat helmet first developed for the British Army in 1941 by the Medical Research Council.
 First worn in combat by British and Canadian troops on D-Day, the Mk III and Mk IV were used alongside the Brodie helmet for the remainder of the Second World War.
 It is sometimes referred to as the "turtle" helmet by collectors, because of its vague resemblance to a turtle shell, as well as the 1944 pattern helmet.
The Brodie helmet is a steel combat helmet designed and patented in London in 1915 by John Leopold Brodie.
 In modified form it became the Helmet, steel, Mark I in Britain and the M1917 Helmet in the U.S. Colloquially, it was called the shrapnel helmet, Tommy helmet, tin hat, and in the United States the doughboy helmet.
 Worn by Australians during WW2 and sometimes known as Panic Hat.
 It was also known as the dishpan hat, tin pan hat, washbasin, battle bowler (when worn by officers), and Kelly helmet.
 The US version, the M1917, was copied from the British Mk 1 steel helmet of 1916.
 The German Army called it the "Salatschüssel" (salad bowl).
 The term "Brodie" is often mis-used.
 It is correctly applied only to the original 1915 "Brodie's Steel Helmet, War Office Pattern".
The Modèle 1978 helmet is a modern military steel helmet used by the French Army under the "F1" designation and commonly called "heavy helmet" (other nicknames include "locomotive skin cap").
 It replaced the Modèle 1951 helmet, and is superseded by the SPECTRA helmet.
The Pickelhaube (plural "Pickelhauben"; from the German "Pickel", "point" or "pickaxe", and "Haube", "bonnet", a general word for "headgear"), also Pickelhelm, was a spiked helmet worn in the nineteenth and twentieth centuries by German military, firefighters, and police.
 Although typically associated with the Prussian army who adopted it in 1842-43,
The Modèle 1951 helmet was a military helmet used by the French military (Army, Navy, Air Force and Gendarmerie), iconic of the Algerian War.
 It replaced a variety of helmets used during the Second World War, including the Adrian helmet, Modèle 1945 helmet and American-supplied M1 Helmet.
The SSh-60 (СШ-60 (Russian: стальной шлем образца 1960 года/stalnoy shlyem, or steel helmet) was a product improvement of the Soviet SSh-40 steel helmet of the Soviet Army and entered production around 1960.
 It was not fundamentally different from the previous World War 2 era SSh-40.
The M15 Adrian helmet (French: "Casque Adrian" ) was a combat helmet issued to the French Army during World War I.
 It was the first standard helmet of the French Army and was designed when millions of French troops were engaged in trench warfare, and head wounds from the falling shrapnel generated by the new technique of indirect fire became a frequent cause of battlefield casualties.
 Introduced in 1915, it was the first modern steel helmet and it served as the basic helmet of many armies well into the 1930s.
 Initially issued to infantry soldiers, in modified form they were also issued to cavalry and tank crews.
 A subsequent version, the M26, was used during World War II.
Stahlhelm (plural "Stahlhelme") is German for "steel helmet".
 The Imperial German Army began to replace the traditional boiled leather Pickelhaube (spiked combat helmet) with the Stahlhelm during World War I in 1916.
 The term "Stahlhelm" refers both to a generic steel helmet, and more specifically to the distinctive (and iconic) German design.
Hawley Products Company is a manufacturer of loudspeaker components.
 The company is the oldest manufacturer of loudspeaker diaphragms in the world.
 Historically, the company produced a variety of products composed of fibrous or plastic materials, including helmets, globes, microwave trays, automotive components, suitcases, and furniture.
 Most notably, the company is remembered for its World War II military helmets and helmet liners used by soldiers in the United States Army, Marines, and Navy.
 Hawley Products is the original designer of the M1 steel helmet liner.
 The company is also one of the two original manufacturers of the M1 steel helmet liner, alongside General Fibre Company.
 Additionally, Hawley Products designed and manufactured several versions of the pressed fiber military sun helmet used by the US military during World War II.
 The military continued to use this sun helmet throughout most of the 20th century, including Naval personnel during the Persian Gulf War.

Question: What helmet typically associated with the Prussian Army was replaced by a steel helmet during World War I?
Answer: Pickelhaube