Headphones for exercising
The most important thing about headphones for exercising is that they are waterproof, stay in place and can withstand a blow. Triathlonworld has a range of headphones that have these features.
The in-ear solution offers noise cancellation and very good sound quality, but also limits ambient noise in situations where this is important, for example while running or cycling where it can be useful to hear cars and cyclists approaching. Bone conduction solutions do not have this limitation, but they do compromise on sound quality.