If you're in the market for industrial robotics cobots, the first decision often comes down to what you actually need: a full robot arm you can build and control yourself, or a specialized gripper that adds dexterity to an existing cobot. These two products sit on opposite ends of that choice. The ARM-21N4 5-DOF Robot Arm Kit is an unassembled arm with five degrees of freedom, while the PIAB piCOBOT Collaborative Robot Gripper is a handling gripper designed for Universal Robots. The price gap between them is wide enough to signal that these are different kinds of investments.
Quick verdict
Pick the ARM-21N4 if you want a hands-on automation project at a low price. It's a learning tool that can become the base for custom end effectors. Choose the PIAB piCOBOT if you already run Universal Robots and want a dedicated gripper for handling tasks without assembling an arm. You'll pay more for the gripper, but you're getting a purpose-built component.
Comparison
| Feature | ARM-21N4 5-DOF Robot Arm Kit | PIAB piCOBOT Collaborative Robot Gripper |
|---|---|---|
| List price | $119.23 | $1,169.95 |
| What it is | Unassembled 5-DOF arm kit | Gripper for Universal Robots |
| Construction | Bearings at movable joints | Handling gripper with robotic claw |
| Origin | China | Germany |
| Condition | New | New - Open box |
Where each product wins
Go with the ARM-21N4 when your goal is to build and customize. The kit gives you the skeleton of a robot arm, and the gripper holder fits suction cups, electromagnets, forks, and claws, so you can swap tools as your project evolves. It's the lower-priced entry into cobot-style automation.
Pick the PIAB piCOBOT when you need a gripper designed for Universal Robots. It's built as a handling gripper, and its robotic claw construction suits industrial tasks where you want a clamp at the end of the arm. You're paying more, but you're buying a specialized component rather than a bag of parts.
Product notes
ARM-21N4 5-DOF Robot Arm Kit
This kit is for shoppers who want the satisfaction of assembling an industrial-style robot arm from the ground up. The five joints are driven by digital servos, and all movable joints are supported by bearings, which helps keep motion stable. The key feature is the gripper holder: it's designed to fit suction cups, electromagnets, forks, and claws, giving you a wide range of end-effector possibilities. Upper arm is 121mm, middle arm 111mm, and forearm 61mm, so you know the approximate reach before you buy. The catch is that it's unassembled, so you'll spend time building before you can run any tests. If you're comfortable with the build, this kit offers a low-cost way to start experimenting with cobot-style automation.
PIAB piCOBOT Collaborative Robot Gripper
This gripper is the straightforward choice when you already have a Universal Robots cobot and need a clamping solution. It's classified as a handling gripper, and the specific model PCO.U1.M01.T.MC2.S221PA.X.6.CC.A.XXX (MPN 9938239) points to a product built for a particular set of tasks. Made in Germany, the piCOBOT is designed to work with Universal Robots, so you don't need to adapt it for a different brand. The condition is listed as New - Open box, which is something to weigh if you require a sealed unit. It's the higher-priced option in this comparison, but for a business automating a production line, the specialized design can justify the cost.
Final choice by use case
If you're a hobbyist, student, or prototyping engineer who wants a five-degree-of-freedom arm to tinker with and adapt, the ARM-21N4 is the natural fit. If you're a manufacturer or integrator running Universal Robots and need a gripper for handling tasks, the PIAB piCOBOT is the product to buy. The decision comes down to build-it-yourself versus buy-it-ready.
