A Gripper is shown IN the Robot kit in its main and largest photograph, but then below the kit it says "frequently bought together" then shows a similar looking Gripper and a Servo...

Can you give me the details of specification robotic arm?

LOL, John if I had to guess, the first (and second) respondent doesn't use the English language as their primary language. To the third DFRobot Support Mod, you might want to ensure whomever is interacting with U.S. / UK / English speaking people is capable of answering clearly. These questions are fairly clearly given and shouldn't be difficult to answer, clearly. From Jack Strawb's response on the servo's I'd suggest you hire him. He seems more than knowledgeable, competent and could probably be a great engineer as well, lol... Life, fun.

**. I was thinking of buying this and had the same question. Given this answer from support, DFRobot just lost my business.

The larger servos appear to be DFROBOT DF Metal Geared 15Kg Standard Servos, the torque of which (what it can hold without moving or yielding) is15kg at a distance of 1 cm. That's about 13 lbs at a distance of one inch, or 1.08 lbs at a distance of 1 foot. Keep in mind that in addition to whatever object the gripper is gripping, that the servo farthest away from that object must also bear the load of 4 other servos, the various brackets, screws, nuts, wires, and the gripper itself.

The smaller servos appear to be Hitec 31311S HS-311 Servo Standard Universal, which carry less load, just 51 oz at their maximum voltage at a distance of 1 inch. That's 4.25 oz at a distance of 1 foot.

You can screw link Servo Driver and the Gripper.