The Goa'uld bodice, also known as the Jaffa Creation Device or Pouch Creator, is a device once used by the Goa'uld to create a symbiote pouch in humanoid species for the purpose of creating Jaffa. The device is capable of creating a pouch in humanoid species and removing the species Immune system, which is to be replaced by a Symbiote.
The Goa'uld queen Hathor had such a device with her when she was placed in a Sarcophagus in Mexico. She used the device to convert Jack O'Neill into her First Prime during her failed attempt to takeover Stargate Command and eventually Earth. He was healed by the sarcophagus. (SG1: "Hathor")
It appears that this device is either obsolete or only used by certain Goa'uld, as one of Apophis' priests was seen using a knife and a Goa'uld healing device to create a pouch in Rya'c, although this may be because Rya'c was already technically a Jaffa. (SG1: "Bloodlines")