You can press the phone into the holster case to protect the phone and then attach the case to the belt clip or pocket clip. The button on the back of the case attaches to the case to the clip. The following pictures show the front and back of the holster case.

When your phone is in the case, you don't have to remove the case to charge the phone.

Power
Power source type	Not supported
Design
Mobile device type	Telephone
Proper use	Belt
Product colour	Black
Type	Passive holder
Compatibility	Cisco Wireless IP Phone 8821 / 8821-EX
Multimedia
Built-in speaker(s)	No