The upper puzzle pictured is made of 1/8" plywood for the inner box and 1/8" Maple/Walnut for the outer faces. The lower puzzle is made of 1/8" plywood for the inner box and 1/8" Baswood for the outer faces.
Interlink
This is a box with not just one or two sliders, but 24 sliders, four on each side. Not hidden sliders, not only quite visible, but with another piece sticking out, to help you move them. Four of the sides are overlapped at one end, so, are these four the top, bottom, front and back, or the front, back, left and right, or the top, bottom, left and right? No way of telling. Just about every slider must be moved, either inwards or outwards to open the box, but there's only one that will move to start with. There are a couple of sliders that don't really do anything, but how do you tell which is which? 22 moves to open the box, but hard to find those moves.
The size of the box is 4 inches each way, and is made from 1/8" wood and plywood. If you purchase a kit with hardwood faces you can choose to have the slider grips and covers be a different hardwood (Ash, Cherry, Mahogany, Maple or Walnut).
This BH puzzle kit has alignment pegs built into the parts to make assembly easier and virtually every part in the kit is labeled.