Practical and innovative, this Jumbo Carbon Fiber Bobbin Threader, w/Half Hitch Tool, like all Dr. Slicks Jumbo Tools, is designed to be easy to see, easy to grab, and won’t roll around on your bench, making for a pleasurable and efficient tying experience. It pulls your thread through the bobbin tube like a dream and has a half hitch tool on the end. The durable carbon fiber handle has a 10mm diameter.