The Claves Astrologicae deck is an amazing companion to the Arcana Iris Sacra deck. It acts like a significators during a tarot reading (pieces that add clarity to the reading).
The cards are small, but well-crafted with all 12 astrological signs, with some Moon phases and etc.
The artwork (the same as the Iris Sacra) is perfect and amazing. Worth the bucks that were well-spent!