A simple but effective instrument for testing and measuring tip extraction flow rates in litres/min. Simply remove the silicon hose from the soldering iron and plug the hose onto the meter gland. Hold the meter upright and read off the centre of the floating ball. Tip extraction should measure 28-30 litres/min (based on 5-6mm bore tubes). Smaller tubes block easily (which is why we dont supply smaller than 5mm!) but 3-4mm bore tubes would acheive around 20-25 litres/min.