It is possible to buy all types of covers online, including cheap duvet covers too. However, the double covers are perfect for a twin duvet or a king or queen one also. These covers are extensive and fit the larger duvets perfectly. They are tricky to get on; however, with a little bit of help, it all comes together nicely. The critical factor when it comes to the larger covers is making sure the size is perfect. It should not be too large or too small, so choose something ideal. You can easily buy so many buy duvet cover sets online, including the double ones, so keep an eye out.