Long-range tachyon scanner

From Memory Alpha, the free Star Trek reference

The long-range tachyon scanner is a tachyon-based sensor technology developed by the Dominion in 2375. The scanner could be mounted on Jem'Hadar attack ships and is capable of detecting cloaked Klingon warships at long range.

This device was first encountered in battle when a Jem'Hadar fleet detected General Martok's cloaked birds-of-prey after their raid on Trelka V. (DS9: "Once More Unto the Breach")

It seems Klingon cloaking devices are different from their Romulan counterparts, as Romulan cloaking devices can be penetrated with antiproton beams.