While bomb builders often improvise their own switches and triggering devices, they are equally apt to purchase and use commercially available switch products. The advantage of them is reliability through factory quality control, and the fact that they are quite inexpensive.
Because of their reliability, commercial push button switches, toggle switches and rocker switches are commonly used in improvised explosive devices. They are particularly common in suicide/homicide belts and vests.
Securesearch, Inc. uses a wide range of commercial switches in our products. They have an x-ray signature that is quite different from that of any improvised switch. For training purposes, it is important that screeners and bomb squad members be shown examples of many different switches, and their x-ray images.