Shroud

Shroud is the term used to describe the Jem'Hadars' ability to cloak themselves. This ability gives the Jem'Hadar a great tactical advantage on the battlefield.

A Jem'Hadar's ability to shroud is affected by the supply of ketracel-white within their system. Jem'Hadar low on white often lose the ability to shroud. (: "Q, Time and Again")

Federation sensors have difficulty detecting Jem'Hadar when they are shrouded, a problem not shared by Dominion sensors.

To combat the advantage the shroud gave the Jem'Hadar during the Dominion War, Starfleet devised several countermeasures to detect shrouded Jem'Hadar. They included the use of pressure mines, tripwires, footfall sensors and UV dust.