Hi Kevin
The image has two old Agni 20´´´chimneys, the new one was placed on the center (black background).
This shape is tottaly different from the Vulkan and Kosmos Vulkan range.
The break bettween the base and the onion shape (where the flame is) has a different diameter. The onion shape is designed for each one. This specific shape is wonderful, it moulds the flame better and gives a good light, even in the Matador the flame is improved and the chimney is not designed for that range.
Those new chimneys were hand blown and hand cut by experienced artisans. They are a bitt thick and they work perfectly.
best
António