The Dovetail series are premium anodised aluminium puzzles designed by Will Strijbos. The contrasting two-colour dovetail design is produced in three editions: the concave, convex and T. This larger version measures 60mm in length and weighs 171g. 

This is a special concave edition that was custom made for a bank to distribute amongst it's employees around 10 years ago, and is now available in very limited quantities.