Red, blue, and green are ballpoint pens. Black is probably 1.18mm. The barrel has a pattern. The mechanism works fine, but the BP refill standard is unknown. The refill retracts when the top button is pressed. - Model Name: Stylus Pen - Color: Silver - Pen Tip Type: Ballpoint Thank you for looking. Caran d'Ache Ballpoint Pen 1.18 Mechanical Pencil Ecridor Discontinued Discontinued 4-color Pendulum Type