A waldo is a type of mechanical manipulation device, taking the form of an artificial arm and hand.
The first uses of waldos were to manipulate objects in hostile or dangerous environments, such as in "hot cells" in radiation labs. Later they were used by humans as an alternative (or an adjunct to) artificial limbs. People who were too crippled or injured to use conventional prosthetics could have waldos fitted to their travel chairs. Also, some races (most notibly, some of the Solomani "uplifted" species) must use waldos to substitute for their lack of "hands".
The major example of waldos used by a species is the case of the Dolphins. Early versions (TL 9) were worn as a harness or mounted on a TeeSuit, and were controlled by movements of the tongue and head. They were very clumsy and weak, only able to move weights of 25 kg or less. They cost Cr150,000 and weigh 20 kg.
At TL 12, medical and robotic advances allow the surgical implanting of neural control plugs in Dolphins. Waldos can then be directly controlled by the brain of the user, becoming far less clumsy. At TL 15, Dolphins using waldos are as adept as humans. Strength is also enhanced, allowing objects of up to 100 kg to be freely manipulated. Cost of the operation is Cr150,000 at TL 12, dropping by Cr15,000 at each subsequent tech level. TL 12 waldos cost Cr250,000 and weigh 10 kg.