The prehensile tail ability is written thus:
Prehensile Tail: Many tieflings have tails, but some have long, flexible tails that can be used to carry items. While they cannot wield weapons with their tails, they can use them to retrieve small, stowed objects carried on their persons as a swift action. This racial trait replaces fiendish sorcery.
The question is what constitutes small items? In my opinion, the immediate things I think about are wands, potions, spell components, metamagic rods, keys, foodstuffs, but is there a definitive list as to the cutoff of stowed items?
For example: I use my prehensile tail to retrieve a dagger stowed in my belt. While I do not use the tail to wield said weapon, I transfer the weapon from the tail to my hand to wield. Is there also weight or shape considerations for this maneuver? (Retrieving a wand is different than say retrieving a ball, or a box, or a plate, etcetera)