Brainteaser Hollow Cube 131413
This is a Meffert's Hollow Brain Teaser Cube that's produced by the good folks over at Project Genius. They make various levels of challenging puzzles!
Project Genius uses a 5-star rating system for difficulty with 5 being the most difficult. The goal of this puzzle is to make each side has 9 unique colors.
Great for any fan of brain teasers!