The self-locking knotting hooks from Prym are the perfect tools for this manual. Once the end of the knotting hook passes through the canvas, the hook's clasp automatically opens. This allows the thread to be lifted and pulled through the canvas. During this process, the hook closes automatically, preventing the thread from slipping. The two hooks for Smyrna and Feinsmyrna are equipped with a wooden handle, allowing for comfortable work.