The Nirvana Fly Tying Base comes with two options. Choose from the aluminum base with the grooves cut into it for easy hook and bead storage. The Steel Base comes with a flat surface and no grooves with a wider base. If you bought a Nirvana Rotary Vise and didn't get a C Clamp for it, this is where you will get it (C Clamp is for the Nirvana Rotary Vise).