Container of approx. 50ml with organic liquid beeswax (100% natural ingredients: beeswax, carnauba, linseed oil).
Trick of the trade: In the Pianel tutorial we use liquid beeswax to coat the spine and hinges. This will provide the surface of the paper with some resistance to abrasion, as well as 'lubricate' the hinges a bit (where paper is rubbing against paper).
Liquid beeswax is also very suitable to treat your paper for extra protection and a little gloss.