Payload

Payload is the first number to check for any robot that moves things. For an arm it is measured at the wrist and includes the gripper, so a 5 kg arm with a 1.5 kg gripper really handles 3.5 kg of goods. For a delivery robot it is the total weight on its trays.

Payload usually drops as the arm stretches out, and humanoid figures often describe a short lift, not hours of carrying. Ask for the payload at full reach and for the continuous figure, then keep a 20 to 30 percent margin.