Meffert's Challenge MEGAminx - Speedcubing Puzzle - Level 10 Mindboggling by Puzzle Master Manufactured for Speedcubing Authentic Meffert's Challenge Rotational Puzzle 3 1/4 in x 3 1/4 in x 2 2/3 in / 8.2 cm x 8.2 cm x 6.8 cm Level 10 - Mindboggling Adjustable springs for fine tuning