• Frequency Response - 10-20,000 Hz
• Dynamic element for extended frequency response
• Unique earbud design directs sound into the ear canal for deep bass and extended frequency performance
• Speciality ear cushion material forms slowly in the ear canal to provide a custom fit and maximum isolation
• Includes replacement ear cushions

A Portable headphone is a headphone that is used on-the-go. Portable headphones tend to be smaller, more lightweight, and may have features that lend themselves to listening on-the-go, like carrying cases or collapsible headbands.PRODUCT FEATURES:Dynamic element for extended frequency response;Unique ear bud design directs sound into the ear canal for deep bass and extended frequency performance;Improved slow memory ear cushions deliver better fit and isolation;Includes replacement ear cushions;Reliable L plug for improved reliability and durability.

These ear buds are comfortable and they block out surrounding sounds better than noise canceling ear buds. The earpiece is made of neoprene, the same material as earplugs.

I have 2 pairs of these ear buds. The first pair has great sound, very clear. However, the second pair has too much bass. I would recommend this product if you get a pair that is clear like my first pair but not the second pair unless you have an equalizer.
But these are the most comfortable that I have tried.

After reading for several weeks about sound isolating earbuds I settled on the Koss Sparkplug earbuds with self expanding foam earpieces. I read everything from that they were ok, or junk, all the way to being the best ever. IMHO these were my observations. 1. I never could get standard earbuds to fit right or stay in my ears without one side or another constantly falling out, and if I did manage to finally get them to stay in, my ear(s) would hurt and I would get a headache after a very short period. with these because of the self expanding foam, these fit fantastic and after a while I even forget I'm wearing them! (That is a huge plus to me) by the way, Koss includes an extra set of the foam pieces. 2. despite what the naysayers are saying, these are hardly overrated, people are buying so many of them because they sound good. The sound is incredible coming from such a small device. I never have had such deep rich bass from any earbud no matter what the price, and I've owned very expensive sets. The sound I get from these rivals my full size headphones, and that is saying a lot. most any earbuds in this price range are tinny sounding pieces of junk. These sound incredible. I've read that for some folks these are too bassy and there are simple modifications such as covering the little holes on the back of them with common tape to tighten up the bass and bring out the mids and highs better. With my setup at home I have an EQ so it was no trouble for me at all to dial them right in for superb sound. For folks using portable devices without an EQ, they might want to try the simple mod or even try placing them less deep in the ear. Some folks said after experimenting with them a bit, they found a "sweet spot" for great sound without mods of any type. 3. I am a music freak, an audiophile, and a musician, and a producer for a popular radio program, and in my opinion they are awesome. What does that mean? NOTHING! why? because sound quality is subjective to each individual. To my ears these sound great, and the stereo imaging is incredible, I'm hearing things I never noticed before. I have heard before that this a common trait in Koss products. but to others they will sound different. The sound isolation for me was perfect, but people should take care using these in area where the might have to hear, such as jogging near traffic etc. 4. PRICE,- as inexpensive as these are, they sound better than ANY other earbuds I have owned regardless of price! I saw one person mention in review that even with any mods they still only sounded like 11 dollar headphones. maybe to him they did, I disagree entirely. At full retail they run about $15.00 but I have seen them higher and lower, but they are definitely worth the risk to try them for yourself and experiment a bit. I LOVE mine. If you don't, get a refund, or give them to your kid, or a friend. I guarantee someone will love them! 5. The no questions asked Koss lifetime guarantee. - if something happens to them, it doesn't matter what, stick them in an envelope and mail them to Koss with $6. and they will repair or replace them and send them back to you. So if they short out or anything, or you step on it by accident, no worries, you can get a new set for about half price forever with no limitations. you just can't beat it.
7. In conclusion, at this price point, or even at a much higher one, you'd be hard pressed to find a set that sound this good, so take a chance and find out for yourself. Don't trust my opinion or anyone else's' - you can always get a refund or give them away if they don't sound good to YOUR ears! :)

If you don't want to spend alot - but want real good sound in an ear bud - these are for you. I can't bring myself to buy any others - I'm hooked!

You can't seem to find these buds locally anymore; so I keep trying to buy another low-priced bud at local stores and always end up returning them. I love these Koss SparkPlugs. Crazy thing is that when I could find them locally, about 2 years ago, they were $15! Now they are only $10.20!?!! They are selling a version of these Koss SparkPlugs with a built-in mute button, but I *strongly* recommend *against* that model, because the mute button goes bad in no time - even if you don't use it! - and you end up with no sound and have to throw the buds away! Is that stupid or what-? I call it planned obsolescence! Get this model without the mute button. If you really need to mute just pull out the plug or rip off the ear buds. Simple enough?! Duh!

They have great sound and fantastic response (loud). One thing I like to do with them (and I do it immediately when I remove them from the packing) is to turn the black expanding-foam cushions around to get the ultimate tight-fit in my ears. It doesn't hurt or get sore - just makes a really tight fit which gives the best sound. There's just one trick to reversing the cushions: you have to also remove the small straw (which runs down the middle - its easy enough to do - just don't lose it as it is small) and reinsert it into the cushion in the *opposite direction*; this is necessary because the straw is fatter on the end which fits onto the post on the earbud, where it attaches. You'll see the post whenever you remove the cushion. The cushions seem to last forever (for me anyway) - so if one seems to be falling off I just glue it on to stay. What breaks on every earbud/headphone, no matter what the price, is the connecting wire. So live with it. That is what will make you buy your next SparkPlug when it comes time to. Might as well buy 3 and get the Free Shipping like I just did! Can't beat that one. Thank you, Amazon.com. (No I don't work for them OR Koss!)

They're great on the subway or mowing your lawn/blowing leaves this Fall (another favorite of mine - underneath soundproof hearing protectors! Rockin'!) If you like the price - buy 'em and enjoy. These are great buds. Period.

I've bought these headphones about 4 times. I probably shouldn't have after the 1st time but they are so good while they last. Every pair I have owned has died, or the earbud comes off, or one of the earbuds eventually breaks (disconnect), as I found out my current pair are right now and I can only hear out of the left one. They are amazing and fit great and have perfect sound....while they last.

I'm on my third set (They'd get 5 stars, but when you use them every day (like I do), the wires eventually break and you wind up with only one earphone working (which I then use in my computer at work). I've always had problems with earphones falling off my ears, regardless of shape (and I've tried most of them). The foam on these really is excellent, so that once inserted, they remain comfortably inserted (I've had them in for 6 hours straight in long air flights without any discomfort). The sound quality is actually pretty good - about as good as one can get with in-the-ear phones without spending a couple of hundred dollars. And these are about the only kind that fit under my motorcycle helmet, providing much better sound quality than is available in helmet speakers.