The Hakko 373 Solder Wire Self Feeder allows the operator to simultaneously feed wire solder and solder with one hand, while freeing the other hand for other tasks.The Hakko 373 Solder Feeder allows the operator to solder with one hand by feeding the solder directly to the iron. This process controls solder feed consistency, elimates the need for 'transfer soldering', while also freeing up an extra hand. The 373 Solder Feeder requires the proper adjustment ring for the solder diameter size you are working with, along with the corresponding tube unit that will run the solder up to the handpiece, and the guide pipe that takes the solder from the tube unit and feeds it to the tip of the iron. For those working with a bottom feed type unit a special receptacle for your handpiece has been designed with the guide pipe in mind.

• Solder return (retraction) mechanism that pulls back a small length after feeding to reduce thermal stress and avoid solder drooling. 
• It does not come with the iron, solder wire, tips, or optional mounting / interface parts. You’ll need to assemble/configure with optional components (adjustment ring, guide pipe, tube unit, iron receptacle) depending on your soldering iron model and solder diameter. 
• Newer tube units allow bottom-feed (solder feeding from underside of tip) for better heat bridging and reduced clogging from flux vapors.