One of my worst consumer experiences ever. After waiting a long time for delivery, I was immediately disappointed to find that the Penna keyboard did not work with my MacBook Pro computer. Apparently Elretron used an incompatible version of Bluetooth, making the Penna keyboard the only Bluetooth device I was unable to use with the laptop. Since the Penna would not pair with my Mac, I decided to use it instead with my Windows 10 Lenovo laptop. When it worked, the keyboard was fine. Unfortunately, it often did not work. Like many wireless keyboards, the Penna would occasionally drop keystrokes. But even worse, it would often stop working entirely. Many times I had to re-pair the Bluetooth connection to get it working. Then the Penna stopped working entirely. I could no longer re-pair it, I could no longer remove the prior connections, and so on. I tried all the suggestions in the hard-to-read instruction sheet, then again contacted the company's technical support. They suggested that I try various things to reset the device, but everything failed. Next I discovered that the Elretron company has no real support in the United States. When I asked their technical support about returning the keyboard for repair or replacement under warranty, they told me I had to ship the defective keyboard to Korea. Yes, Korea! Since current international shipping rates make that impractical, they then said I could ship the keyboard to California. Three months after my shipment I had still not heard back from them, so I contacted them again. Since then I have been given a continued runaround, and encountered most unfriendly and unhelpful customer service. After more than a couple dozen emails back and forth, I am disgusted with the Elretron company's poor customer service and unreliable Penna keyboard. Buyer, beware.