These ear buds come with three sets of tips, each of them alters the sound quite a bit. The tips allow you to tailor the sound to your needs. Straight out of the box the PureBuds are fitted with the normal silicone ring which is made for shallow insertion and basically just turns them into ordinary ear buds.
The tips are made from a really tough kind of silicone much like the big silicone tip that is supplied with Head-Direct RE1s and RE2s. They cover the big ear bud style sound hole and channel the sound towards your inner ear, except for the silicone ring which really only helps comfort a bit. The double flange tip accentuates the sub bass, bass and midbass a lot, but mangles the highs a bit and has a tendency to compress the sound stage a lot. The natural tip does not alter the sound that much except for a tiny bit more bass and a slightly smaller sound stage.
From the side without a tip on you can see the basic shape of the PureBuds. They are really quite large compared to other more traditional ear buds. This could be because the reverse mounted driver takes up more space than usual. The people behind PureBuds have definitely enhanced the ergonomics by letting the sound hole extend quite a bit from the main body. This means that the body does not conflict with your outer ear, securing a good fit.
Above you can see a comparison between the three types of tips. The first tip is called "surround" and does provide you with the biggest sound stage closely followed by the neutral tip which is in the middle. With the bass tip on you get oodles of subbass, bass and midbass. It is a bit overpowering, but never the less it does what it is supposed to. The design of the tips varies greatly, as the surround tip is just a silicone ring that aides the comfort somewhat. The bass tip is a very smooth double flange tip which provides a good tight fit and boosts the bass immensely, while the neutral tip does not give you a tight fit, and has a textured surface.
The cable used is quite tough and heavy. Unlike the other ear buds I have recently reviewed these come with an L-style cable which is made so that you can easily loop the cord behind your neck.
The mini jack is pretty ordinary and is quite durable. Since it is a right angled connector you might have some trouble using it with the iPhone Gen 1.