An apparatus comprises a base and an arm. The base has a first section defining an aperture through a thickness of the first section; a second section having a varying thickness along a width of the second section; and a third section, wherein the second section is between the first section and the third section. The arm is pivotally coupled to the second section and rotatable between a first position, in which the arm is positioned proximate the first section of the base, and a second section, in which the arm is positioned proximate the third section of the base.