You can change the wristband of the Withings Pulse using a spring bar remover. Alternatively, you can use a pointed object to compress one end of the spring bar to remove it (step 1), and a thin and flat object to press the spring bar (step 5). You also need a compatible wristband: 18 mm wide (11/16").

1. Use a spring bar remover to compress one end of the spring bar and remove it from the aluminium support. 
   

   

   
   
   
2. Remove the spring bar from the bracelet.
   

   

   
   
   
3. Put the spring bar in the new bracelet.
   

   

   
   
   
4. Insert the spring bar in the aluminium support.
   

   

   
   
   
5. Press the top of the spring bar and drag the other side of the bracelet into the aluminium support.
   

   

6. Repeat this operation for the other part of the wristband.