This is a set of 4, strong, chunky metal brainteaser, "take-apart style" puzzles with a bonus Twisted Nails Puzzle to make a set of 5 puzzles. Each puzzle measures approximately 3 to 4 inches length. Heavy gauge steel makes them quite rugged. Even when your "HULK-Like" friends play with them they should stand up well. For each puzzle the object is to separate and then re-join the two pieces (and know how you did it !!!)These are medium difficulty puzzles. The manufacturer rates one each as: medium, difficult, tough and X-tough. We find them to all fall into approximately the same level of difficulty. Your experience may differ. They will be fun ! It is as much a puzzle to put them back together once separated. For an extra tricky challenge attempt to separate and re-join behind you back. One really knows they have completely solved these brain benders when they can take them apart and re-join them in about 25 seconds. Now you have arrived !! Pocket size, easy for travel.Make great puzzles for taverns, bars, social clubs, youth centers, and senior centers.Great for all ages from 6 to 105 years.Returns of new, unused puzzles are always promptly processed. This item is sold as a bundle. All returns must be the complete new bundle. Great for all ages from 6 to 105 years.