Bker Advent calendar Cataclyst The Bker Plus Cataclyst advent calendar contains everything you need to put together a high-quality pocket knife. Based on the original Cataclyst, the set offers two blades, including one with a nail nick, which enables use in accordance with 42a WaffG. It also includes different handle scales, bolsters, clips and a few surprises that offer numerous customization options. With detailed step-by-step instructions and a video tutorial, assembly is easy to understand. This limited edition set is the ideal gift for knife enthusiasts and a real highlight for any collection.