Description: Widely used for building industrial aluminum frame structures, 3D printers, CNC Routers, CNC cutters and Robotics Projects Made of high quality carbon steel,Nickel-plated for good rust resistance and better performance Durable and practical, high hardness and a long service life surface Half Round Roll In Sliding T slot nut slot, making it simple and convenient to connect aluminum profiles to other parts Hammer head design, mainly used for slot standard aluminum extrusion profiles Specification: Material: Carbon Steel Shape: Hammer Head Thread Type: M6 Slot Width: approx. 7.8mm / 0.3 Inch Overall Size: approx. 20 x 13.36 x 9.36mm/ 0.78 x 0.52 x 0.36 Inch Color: as shown in display pictures Package Includes: 20 Pieces T-type Slot Nuts