CNET has a review of the Jabra BT620s and writes - “The Jabra BT620s headset sports a flexible, though non-adjustable, behind-the-neck design. At either end of the black neckband sit two round, silver earpieces that measure 2.4 inches in diameter. Although the headphones weigh a light 3.5 ounces, they feel heavy when worn. The neckband curves (above the earpieces) can be hooked over the ears to provide a more secure fit, but I found after 10 minutes that the resulting pressure on my ears was quite uncomfortable. Unfortunately, the headset has a tendency to slip off when not supported in this fashion–a serious design flaw, in my opinion. James Kim claims they’re moderately comfortable, and they didn’t slip off his ears. However, he did get a small headache from the prolonged pressure on his ears. Overall, the BT620s may be OK for those with tough ears, but it’s a pain for the rest of us.”

Read more about the Jabra BT620s Bluetooth headset