Safe and suitable wheels for dwarf hamsters. The most popular one used to be the 6.5" silent spinner. Again there have been reports of issues with them not spinning well in 2014/15. Good alternatives are:
Wodent wheel Junior 8"/20cm (known as the Robowheel in Germany)
8" Wodent Wheel (Junior)
Karlie Wonderland wood wheel 8"/20cm (again needs checking for splinters especially on tread areas, and possibly light sanding. Plastikoting recommended.
Wonderland Exercise Wheel: Great Small Pet Accessories at zooplus
New Silent Runner 9" wheel from Exotic Nutrition in the US and available from the Sugarglider Shop and Ebay in the Uk.
Flying saucers for dwarf hamsters - 7" size recommended.