The photos shown are swapped. Both kettles have the same diameter - 5.5", and the difference in capacity comes from different heights. The 1.0L kettle has the stubby triangular spout, and it's aspect ratio shows a lower height. The 1.5L kettle has the pronounced spout, and it's aspect ratio shows it's taller at the same diameter. I am expecting the 1.0L kettle to fit in my Trangia 25 cookset.
bcw1000For anyone who is uncertain about this from looking at the one 'combined' photo in the Description, look at the other photos. The photos of the side of the kettle show the logo and the words "Keith", "titanium" and below that clearly also state the capacity - 1.0l or 1.5l.