Features:

• XBS port increases bass response
• Comfortable open-air design with wide headband
• Frequency response 16Hz-22kHz
• Neodymium rare-earth magnet for rich and powerful sound
• Large-diameter driver units 30mm (1-3/16")

Editor Reviews:

Product Description:
Open Air Design / Wide Band Comfort / Excellent Bass Response

Amazon.com Product Description:
Take your music on the run with Panasonic's lightweight, low-cost RP-HT21 over-ear headphones. Their large, 30 mm diaphragms offer full-bodied sound free of the harshness and discomfort that usually accompany earbud-style earphones. The headphones' open-air design minimizes adverse resonances, and Panasonic's XBS acoustic ports naturally emphasize bass frequencies for rich sound from nearly any source.

What's in the Box
Headphones, data sheet.

Rating : - Good sound, low volume
You do get a stronger bass than expected from such a small headset. However, in order to actually hear the difference, you need to either turn up the volume a lot or press the ear-cuffs to your ears.