LEGO Dark Blue Minifigure Hips and Legs with Dark Gray and Dark Red Pockets (3815 / 41999)

LEGO Dark Blue Minifigure Hips and Legs with Dark Gray and Dark Red Pockets has been used in at least 2 LEGO sets over the past 22 years, since it was first used in 2002. It has a design ID of 41999 which can usually be found molded into the bottom of the part.