Porsche Design P3120 Ballpoint Pen Matte Silver Aluminium. The Porsche Design P'3120 range of writing instruments are manufactured from aluminium.A material widely used in cars and aircraft. Aluminium is light in weight giving the P'3120 range a lightness despite their solid construction. The P'3120 range consists of complementary, twist action, ball pens and mechanical pencils. The ball pens accept standard refills.