Ultra Hard High Difficulty 54 Blocks Cube Luban Lock: This classic Chinese Luban lock cube adopts 54 irregular wooden blocks, only one unique assembly solution. Far more challenging than regular 3D puzzles and ordinary interlocking locks, perfect brain teaser for puzzle lovers over 10 years old Multi Fresh Color Options: Available in solid log, black-white, blue-gray, yellow-blue, pink-white, mint white, black mint color matching versions. Made of solid beech wood, every block fully polished with smooth burr-free edges Ideal Stress & Anxiety Relief Decompression Toy: Great fidget puzzle to release study, work and daily pressure. When focusing on figuring out the assembly logic, it effectively calms irritable mood, helps adults stay away from phones and reduce screen addiction Boost Multiple Logical & Spatial Thinking Abilities: Restoring the scattered blocks requires strong spatial imagination, logical reasoning, patience and step-by-step planning. Constant trial and error exercise kids' concentration, problem-solving skills and 3D space cognition Premium Puzzle Gift for Puzzle Enthusiasts: Comes with a solid wooden storage frame to hold all blocks after finishing assembly. Perfect birthday, holiday, Christmas gift for boys, girls, teens and adult puzzle collectors. Great competitive game prop, classroom extracurricular intelligence activity toy