This is a corner attachment for "Biltema" 4" https://www.biltema.se/verktyg/handverktyg/klammor/snabbtving-2000018448 Artnr: 20-836 A helping hand when gluing, nailing or screwing corners on small projects in the workshop. It's like having two extra hands! The source file is included so you can easily adjust it to match other clamps.