Gemini by Crafter's Companion are a popular crafting brand which does not let you down.  This is a double sided papercraft square box die with tags. The dies cut both sides at the same time. 
 
This die can create square boxes in three different sizes; 6.1x6.1inches, 4.35x4.35inches and 2.6x2.6inches. 
 
Compatible with most die cut machines.