-----READ BELOW BEFORE BUYING-----
These come in a variety of models for different Macbook chargers. As you know, each MacBook model has a different wattage of power brick so choose the Powercurl model that suits your wattage of charger! All Macbook Models are supported according to the listing.
The one I've linked is, confirmed by Amazon Live Chat, is for the 60W Macbook Charger. Amazon have listings for a 45W in Grey and Blue and also a 85W in Blue. These are dispatched within a standard 1 - 3 day period.
45W Blue: http://www.amazon.co.uk/Quirky-PPRC1-45BL-Powercurl-Cable-Management/dp/B004I1KV1A/ref=sr_1_3?ie=UTF8&qid=1406487349&sr=8-3&keywords=Quirky+Powercurl
85W Blue: http://www.amazon.co.uk/Quirky-PPRC1-85BL-Powercurl-Cable-Management/dp/B003MB3W4U/ref=sr_1_4?ie=UTF8&qid=1406487349&sr=8-4&keywords=Quirky+Powercurl
The way I read it, is that you look at the product code to see which you need - PPRC1-XXXX. For example, PPRC1-45GY means it's for a 45W Charger and the Powercurl is in Grey. Same for the 85W - PPRC1-85BL. 85W in Blue. You get the idea.
Recently been looking for accessories for my MacBook Pro and found this little item to be highly recommended for your charger. As the cable management isn't 100% great on the Macbook block, it helps by allowing you to wrap them up neatly and in a fashion that should help keep your cables from tearing. Apparently this is a must buy and the reviews are excellent.
In terms of why this is a deal, I've found the only real way to get one is the import one from their site, according to them there will be import charges or through an international seller on eBay which goes on to around £15 - £20.
This seems the be the cheapest option if you're from the UK. £7.99 with free delivery BUT you have to wait around 1 - 3 weeks for dispatch. Beats paying import charges and the high cost of others.
Well that was a mouthful to type! Enjoy!