There are two different types of RunPhones: the Winter version and the Summer version.
There is essentially no difference between Winter RunPhones and SleepPhones. They use the same Polartec® fleece, just in different colors.
The Summer RunPhones are made with a very lightweight Polartec® mesh fabric designed to keep you cool. They still have the same thin padded speakers inside. If you sleep on your back, then you may even use these for sleeping! If you sleep on your side, however, there may not be enough padding to keep your ears comfortable. The Winter RunPhones or SleepPhones would work better for that.
We started with SleepPhones, and lots of customers were telling us about the different ways they were using SleepPhones - especially for running. We decided to offer RunPhones so people could have different headphones for different uses. We are happy to offer these headphones in brighter colors.