The strip is placed in the chamber in place of the item to be shot peened, usually near to an area of the item where the result is deemed critical, sometimes located by a special fixture.
Compressive stress introduced by the peening operation causes the strip to deform into an arch, which is measured using a gauge.
Although similar, the specification for Almen strip dimensions of the same type slightly vary from one company/organization to another.
The Almen strips are made from plain carbon steel SAE 1070 and have hardness about 45 HRC.
Another operation to gauge the intensity of a shot peening process is the use of an Almen round, developed by R. Bosshard.