The DC for UMD on Class Features is listed at 20, but what precisely is excluded from the list of 'class features'? The question comes to mind because of the limitations on certain items, such as a string of Prayer Beads. One of the activation requirements is the ability to cast Divine spells. Would the ability to cast Divine spells be a class feature, since even being able to cast spells themselves is a class feature in general? Would a UMD check apply to activate the item provided you knew what it was?
Basically, can I get a +4 CL to my Witch once a day? :p