This is a newer model of the PMX80 which has 10 reviews elsewhere on this site. Based on those reviews and reviews of several similarly priced items, all of which were extremely helpful, and the fact that this was a newer model, I selected this item. I am very pleased with it. I have tried several different kinds of headphones during cardio and other workouts all of which were dismal failures. They fell out on their own, or my hands would catch the cord and yank them out, or the seal was so weak that I had to pump the iPod volume up to max to get the music to a level that I could hear during a workout. These headphones suffer none of those problems. They stay in during both cardio and weightlifting workouts. They seal very well and block out other noise decently so that I could have a more appropriate volume.
If you are interested in sport headphones, you may be also interested in exercise clothing that facilitates wearing them and I recommend the Scottevest Tshirts which have a zippered shoulder pocket that held my iPod and enabled me to keep the headphones cord short so that it did not get caught by any arm movements. These two items in combination eliminated a number of workout-related nuisances and boosted my enjoyment considerably.
UPDATE as of Dec 14: Since I posted the above review in July as a 5 star review, I encountered the same failure that others who have given the product 2 stars in their reviews encountered, namely that one side has failed. The company appears to give a 6 month warranty so I will be mailing it to them for repair or other remedies.
UPDATE as of Jan 24: I experienced difficulty getting a response on my warranty claim and was eventually rejected. The mfr's website has a form to be filled out and sent in via email - but the email address was not a valid one. I eventually reached them using the "contact us" page on their website, whereupon I was told that they would not honor my warranty claim because it was not sold by an authorized dealer - although purchased through Amazon. They referred me to a page on their website that lists the authorized and unauthorized dealers. As a result of this experience, I cannot recommend this product. Potential buyers through Amazon should beware of this experience. I am now using Koss Clippers for exercise and so far, knock on wood, have been pleased.