Diamond Teaser is a mid-level puzzle designed and made by William Waite of the US.
There ae four pieces that fit within the tray. There are many ways these can fit and finding one of these solutions is tricky but you can also find the one solution where the holes leave a symmetrical pattern which is quite difficult.
Made from Red Alder and Black Walnut wood this measures 12 x 7cm. Handmade in the US.