A height adjustability mechanism including a height adjustability mechanism including a spring-biased first lever including a first lever body comprising a first rod hole including a first hole perimeter face pivotally engaged with a guide rail extending through the first rod hole, a spring-biased second lever including a second lever body including a second rod hole including a second hole perimeter face pivotally engaged with the guide rail extending through the second rod hole, wherein the spring bias of the first lever frictionally engages the first hole perimeter face against the guide rail, and wherein the spring bias of the second lever frictionally engages the second hole perimeter face against the guide rail.