What is a retort ring or boss head?
A retort ring is a circular metal loop on a stem that mounts onto a stand rod, giving a flat support platform for a funnel during filtration or a wire gauze during heating. A boss head is the connector clamp that locks the ring's stem onto the vertical rod at a right angle.
SmartLabs stocks chrome-plated retort rings in a range of diameters, giving you a stable support platform for filtration, heating, and general glassware setups.