The new assault units were formed and then developed independently with training different from that of ordinary soldiers. The better trained German army was the first to adopt the concept of shock assault troops with the Stormtroopers, but the Italians followed their example. A training school was established, as noted above, at Sdricca di Manzano, in Friuli. The first units were created in the 2nd Army, and by the time of Caporetto there were 27 units, although only a few actually saw combat. In all, approximately 18,000 men made up the Arditi units. Many of these men saw combat on the river Piave, where the advance of Austro-Hungarian troops was halted. Arditi used to swim across the Piave, clenching a dagger between their teeth and assault the Austrian and German positions on the other bank of the river Piave. These men came to be known as "Caimani del Piave" ("the Caimans of the Piave"). Because Austrian uniforms had a stiff collar, the "Caimani" preferred to use a "resolza" knife, typical of Sardinia (Pattada), as this blade could easily penetrate the collar of the enemy uniform (other arditi formations used a simple dagger). Today, the badge worn by COMSUBIN commandoes shows a caiman clenching a dagger in its jaws. This is an emblem chosen to honor the memory of the "Caimani del Piave".