When shooting indoors you can save wear on your batteries by using the Pentax K-AC106 AC Adapter Kit which includes a power module, AC adapter and AC power cord. It is designed for the Pentax X90 digital camera. To use it you insert the module into the camera's battery port and connect it to the AC adapter which is then plugged into an electrical outlet.
K-AC106 AC Adapter Kit for Pentax X90 Digital Cameras
AC Power Adapter
AC Power Cord