TWSBI Notebooks, paper tailored for fountain pens. 

Comes in Small, Medium, and Large sizes with the option of lined, gridded, or blank pages. 

120 leaves (240 pages). Perforated 

Notebook Specifications:

Universal to all types of writing/drawing instruments, however, specially tailored for fountain pens. 

Small: 3.75 W x 5.5 H (inches)
Medium: 5.25 W x 8.25 H (inches)
Large: 7.5 W x 9.8 H (inches) 

Notebooks all have 120 leaves (240 pages).
Perforated pages on the small size book only.