Sennheiser is a German company that was established immediately after the Second World War to make microphones. Headphones followed, but the company's main headphone fame came in the late 1960s, when it introduced an "open" design. That is, headphones in which the back of the sound reproducer was open to the air, rather than being contained inside a sealed box.
The PX 360 headphones are from a different lineage, though. They use a closed design, but they also prominently feature that stylised "S"' logo, so those in the know will realise that you're wearing quality.
The headphones fold up for carrying around, but in a different way. The earpieces swivel, so that they can form a flattish bundle. They also tilt in a little, but not very much. The supplied pouch is a substantial 195x145mm, and is 60mm thick.
Finished in black plastic with silvery highlights, the ear pieces look compact, but in fact, they are large enough to encompass my ears, so that the soft pads rest against my head. That, and the reasonably gentle grip, made them very comfortable for long-term listening. The padding on the headband is quite thick, so they were gentle on the crown of the head, as well. At 169 grams, they are fairly light, too, and remained securely in place on my head, regardless of activity.
The signal cable is fixed and attached to the right ear piece. It is terminated with a right-angled 3.5mm plug of the kind that tends to work better with portable music players. Supplied with the headphones is a gold-plated 3.5mm to 6.5mm adaptor, allowing you to readily use these headphones with a high fidelity system.
What you don't get is the iPod/iPhone/iPad inline remote control, which won't trouble you in the slightest if you use some other brand of music player. But after using a bunch of headphones with this control, I found that having to scramble in my pocket for the iPod Touch in order to pause a song ended up being a significant drawback.
First, a word on loudness.