LEGO Dark Stone Gray Hinge Brick 1 x 2 Locking with Single Finger (Vertical) On End (30364 / 51478)

LEGO Dark Stone Gray Hinge Brick 1 x 2 Locking with Single Finger (Vertical) On End has been used in at least 14 LEGO sets over the past 20 years, since it was first used in 2004. You can also find this part in at least 16 other colors. It has a design ID of 30364 which can usually be found molded into the bottom of the part.