It’s a bit of a disappointing story, it’s a rough-paper notebook I bought in TK Maxx (a discount store over here, it’s named TJ Maxx in the US). Looks a bit like Lokta paper only more cottony. Soft cover but not leather, it’s like thick soft card with a thin outer coating glued on. Annoyingly I’ve never found another. I use it for sketches and ideas and stick photos of completed projects in it. It’s about half full – I’m looking for the next one at the moment.