A guldin consisted of a set of quarters equipped with all the medical and cybernetic technology and supplies necessary to keep a Grey Orion in reasonable health and operation. They were often sealed against the outside world, with an array of life-support technology, such as air-, water-, and food-recycling mechanisms. This was because exposure to impure water, food, or even air, to light or certain environmental conditions, and even minor accidents, could kill many of the sickly and sensitive Grey Orions. Thus they could rarely leave.
Guldin were also supplied with everything Greys Orions required to do their scientific and technical work, including computers and communications to other guldin. They also had some of the best medical care available in Orion society.
These facilities were closely guarded secrets and well hidden. Guldin could be located deep underground in subbasements or in high-security sections of villas, estates, and office buildings in large, permanent Orion settlements. They could also be constructed deep within a starship, such as a Chariot-class cruiser. (FASA RPG module: The Orions: Book of Deep Knowledge)
Guldin of Grey Orions were in existence at the end of the Dispossession (circa 1288 AD (reference stardate −8/88) that forced Grey Orions out of power and into slavery. The Greys, with their technical knowledge, became valuable and guldin of Grey slaves circulated as spoils of war, theft, and pirate raid, by purchase and trade.
In stardate 0/9003 (c. 2163), a guldin of Grey Orions aboard the Larc secretly transmitted a message to the USS Atmos, a Federation Starfleet vessel. The captain of the Larc became the first Orion charged with slavery by the Federation. However, the captain managed to vaporize every one of the Greys before they could be taken or questioned.
In stardate 1/6908 (c. 2233), a guldin of Grey Orions received sensitive Klingon and Orion information, and relayed it to both the Federation and Romulans in the Parallelogram Affair. Orion authorities discovered the spy ring and interrogated the Greys, but executed them after they refused to talk. (FASA RPG module: The Orions: Book of Deep Knowledge)