The thickness is different. It's all in the pictures. There are 5 in total. This pen is so smooth that I have been using it since I was a student.
Pentel GRAPHGEAR 500 Mechanical Drafting Pencil 0.5mm (5 pcs set) made in Japan
Pentel Graphgear 1000 Mechanical Pencil Pentel Graphgear 1000 Limited Edition - Mechanical Pencils - Aliexpress
Just got a 0.9 Graphgear 500, this is my current gear : r/mechanicalpencils
Mechanical Pencil Lot for sale
PENTEL GRAPHGEAR 500 Mechanical Pencil Metallic Barrel - Select
Pentel GraphGear 500 Automatic Drafting Pencils - Pg523e, Pg525a, Pg527c, Pg529n, 1 for Each
Pentel Graph Gear 500 Mechanical Drafting Pencils 0.7 mm Blue Barrel Pack Of 2 - Office Depot
The best mechanical pencil!! This pencil is so durable and will last you for years to come. The design offers a pocket clip and a capped, replaceable
Pentel GraphGear Mechanical Drafting Pencils
4mm tip length makes it ideal for use with rulers and templates Metallic mesh grip on a slim, beveled barrel promotes control when writing Weighted at
Pentel Arts GraphGear 500 Premium Drafting Pencil, 0.5mm, Black Barrel, 1-Pack (PG525APABP)
Настольный ящик или органайзер для бумаг Wooden Block Pencil