Wraith transporter transformer
From The Stargate Omnipedia
Small cylindrical unit used in Wraith Dart technology for governing the transformation process of a culling beam. More specifically, the transformer is used for converting raw energy into a highly stable, specific stream of power. It is crucial in maintaining the safety and detail of a culling beam's transformation process. Reverse-engineering the device is next to impossible.
KEY EPISODE
Duet - Dr. Zelenka pulls a damaged transporter transformer from the wreckage of a Wraith Dart, informing Colonel Sheppard that it is his mission to duplicate the technology to reinstate Lieutenant Cadman.