It's the Inserto di misura KÄFER a cono 45°, a simple yet handy tool for measuring and marking cone-shaped objects. You'll use it to ensure precise measurements and accurate cuts, making it a must-have for any DIY enthusiast or professional. With its M2.5 thread, it's ready for use with standard measuring tapes and tools. Perfect for architects, carpenters, and anyone working with cone-shaped objects, this insert helps you get the job done quickly and accurately, saving you time and frustration.