Pros: Secure fit to a Nano
Cons: Only fits a Nano
I was surprised that there were two CordShrinks in the package. One is thicker than the other like they were designed for different earbud wire gauges or lengths. I found the thinner one to be plenty of cable storage capacity for OEM and aftermarket earbuds.
There are no auto winding springs. It's a plastic spool that clamps onto the Nano's clamp. It has a small hole at each corner to lock in the desired free cable length.
I like the CordShrink. It makes the Nano a better managed sound system. The thing I like the best about the CordShrink is it makes it a lot tidier to use only one earbud. I like to use just one earbud and this little gizmo is great for managing that unused bud.