A "distilling link with thermometer neck" refers to a specialized piece of lab glassware, often a Y-adapter or distilling head, designed to hold a thermometer at the optimal position (just below the vapor path to the condenser) during distillation, ensuring accurate temperature monitoring for separating liquids by their boiling points, crucial for science and home distilling. These adapters typically feature standard ground glass joints (like 24/40 or 19/26) to connect to flasks and condensers, with a side arm for the thermometer.