Maxsima - AA Battery Holder for Pentax K-500, K500, K-50, K50, K-30, K30, KR, Kr Pentax D-BH109 have (Holds 4 AA batteries for backup power) D-LI109. (Electronic devices)
fast delivery, look a little fragile but easy to use. good troubleshooting solution when the electric network is not (more) available. However, I have not yet tested the complete autonomy in number of pictures with 4 new batteries. The set is heavier