There are 2 spool caps and 1 cone adapter included. These are used specifically for different types of spools. The idea is to keep the spool from turning while allowing the thread to spool off with no resistance. The small cap is intended for small-diameter spools. Note that the spool is the plastic core that the thread is wrapped on. The larger cap is for medium to large spools. The side placed against the spool should be larger than the spool itself. This way, the thread spools off on the edge of the cap, NOT on the edge of the spool. When pushed all the way down on the spool, they prevent it from turning as well.

After securing the spool or cone, the thread must pass through the exit hole opposite the spool pin. At this point, the thread is free to go wherever you would like. The guidewire keeps the thread clear of a cluttered sewing table. When placed vertically with the guidewire extended up, it stands 15 inches tall, clearing most sewing machines' tops. As with any external thread holder, care should be taken to keep the thread clear from obstructions or moving parts.