My very fat vintage Filofax I snagged on eBay along with some pretty charms. This is a vintage model called the Filofax Cavendish with 30mm rings in the personal size which is
Organizer . Personal Organizer . Planner . Filofax USA
Philofaxy: A5 Malden with 30 mm rings
Conversion/Repair Kit for Standard A5 Filofax 6 Rings Binder 30mm 19.19.70.19.1 | eBay
Filofax Finsbury Personal Size Rings - YouTube
Amazon.com : Filofax The Original Leather Organizer Agenda Weekly Daily Planner Ring Binder Calendar with DiLoro Ballpoint Pen (Personal, Stone 2022&ND) : Office Products
Philofaxy: Ring Capacity
Filofax Standard Ring Binders A5 A6-personal Pocket Mini and - Etsy
ORGANISERS
STEP 1- 6 RING MECHANISM - 30MM - Pocket A7, B6, Personal or A5 - Gold — The Leather Quill Shoppe