This low-temperature addition funnel is used in chemical syntheses such as the preparation of block copolymers that require high vacuum techniques. The funnel features a large diameter ring seal between the coolant container and the addition funnel body, thereby reducing stress and permitting use of a wide range of coolants, from ice water to liquid nitrogen. The open cup design of the coolant chamber allows for easy addition of coolant, particularly dry ice chunks, without the annoying "blow-back" associated with other funnel designs. Grease-free Chem-Cap® 0-4 mm valves on the pressure equalizing arm and lower inner joint permit the funnel contents to be kept under inert conditions prior to use or during loading. A 14/20 outer joint is sealed on the funnel body just above the coolant chamber for use with septa for syringe sampling or cannula transfers. The funnel has a convenient drain tube on the rear of the coolant chamber. Available in 50 or 150 mL sizes with a 14/20 or 24/40 lower inner joint.