This is a Brand new Genuine Dyson battery to fit the following models when fitted with a screw release type battery: DC31,DC34,DC35,DC44. Compatable Batteries are aso avalible.  
 
There are two types of batteries for these models. One is secured with  screws (Type B)  the other is push fit  where the battery is released with a button on the back of your vacuum handle.
 
* Do not leave your cordless vacuum on charge all the time. They only take 3-4 hours to charge, once fully charged switch them off at the plug socket to prolong the life of your battery*