These colourful plastic Super Grip 15cm embroidery hoops are great for embroidery or cross-stitch.
 
These make an excellent frame for a finished piece of embroidery or cross-stitch.  Put your fabric into the hoop, stitch your design, then trim the fabric at the back leaving a wide margin.  Stitch it tight and then hang your project on the wall!
 
Here's a great video explaining how to use your hoop as a frame: 
https://www.youtube.com/watch?v=KdGpmTw6a2Y