A rule assembly comprising: a housing; a reel rotatably mounted in the housing; an elongated blade arranged to be wound on the reel and having a free end configured to extend through an opening in the housing; an end hook member attached to the free end of the elongated blade, the end hook member including a mounting portion connected to the free end of the elongated blade and a hook portion extending generally perpendicularly from the mounting portion at the free end of the elongated blade; the hook portion being constructed and arranged to extend downwardly below a bottom surface of the housing when at the opening in the housing, when the elongated blade is in a fully retracted position; the opening having an upper portion disposed above the elongated blade and the mounting portion when the elongated blade is in the fully retracted position; the housing having a flexible cover overhanging the upper portion of the opening to inhibit penetration of debris into the opening; wherein the flexible cover is positioned to be flexed by the end hook member upon impact by force thereon to absorb force from the impact and permit movement of the end hook member into the upper portion of the opening; characterized in that the upper portion of the opening has a height dimension (H T) extending above the hook portion that exceeds a height dimension of a portion of the hook portion that extends downwardly below the bottom surface of the housing; and further characterized in that the flexible cover partially covers the upper portion of the opening and in that a gap (H G) is provided between a top surface of the elongated blade and the flexible cover. a housing; a reel rotatably mounted in the housing; an elongated blade arranged to be wound on the reel and having a free end configured to extend through an opening in the housing; an end hook member attached to the free end of the elongated blade, the end hook member including a mounting portion connected to the free end of the elongated blade and a hook portion extending generally perpendicularly from the mounting portion at the free end of the elongated blade; the hook portion being constructed and arranged to extend downwardly below a bottom surface of the housing when at the opening in the housing, when the elongated blade is in a fully retracted position; the opening having an upper portion disposed above the elongated blade and the mounting portion when the elongated blade is in the fully retracted position; the housing having a flexible cover overhanging the upper portion of the opening to inhibit penetration of debris into the opening; wherein the flexible cover is positioned to be flexed by the end hook member upon impact by force thereon to absorb force from the impact and permit movement of the end hook member into the upper portion of the opening; characterized in that the upper portion of the opening has a height dimension (H T) extending above the hook portion that exceeds a height dimension of a portion of the hook portion that extends downwardly below the bottom surface of the housing; and further characterized in that the flexible cover partially covers the upper portion of the opening and in that a gap (H G) is provided between a top surface of the elongated blade and the flexible cover.