color classification:

Pen (6mm)

Pen (9mm)

Pen (12mm)

Pen (15mm)

Pen (18mm)

Function pen (watercolor)

Qiu Ju Pen

Plaid pen

Phototherapy (round head)

Phototherapy (oblique head)

Phototherapy (Flat Head)

Phototherapy (square)

Oblique Dizzy Pen

Sweep Pen (Gradient)

Color:

Metal pen holder (per metal pen cap)