Finally had some time at the work table the other day — more of the colourful “Ribbed” cosy design.
The one above is sized for a standard 4-cup teapot but because the design cleverly expands like a puffer fish it can accommodate one a little larger or one with a wide spout to handle dimension when it’s popped out like a tent (see instructions below).
If your teapot is large — or you just like the look — pull gently on opposite sides and the stiff felt will pop out like a puffer fish to wrap around the teapot.