Gel Pen M&G Office 0.7mm Model: AGP13275 Single Piece Price. Gel Pen M&G Office 0.7mm Model: AGP13275 - Gel pens, which uses gel ink was first crafted in the 80s; it is a fusion of oil and water-based inks and is water-resistant. Gel pens are similar to ballpoint pens, but write, or...