constructed from a central wall 154 also known as a center wall 154 and a back wall 160 in a t shape the lock arm catch 150 is shown as a lock encasing offset 158 which operates with the locking finger 186 of the lock arm 184 a closed position retention mechanism 162 is shown mounted on the center wall 154 and is shown as a friction retaining projection 164 also known as an engagement tab 164 which is adapted to wedge inside the compaction cavity 124 of the first elongated arm 106 to hold the squeegee 100 in a compacted position the distal end of the second arm defines a second arm tip end 166 also known as a second arm cleaner end 166 the second arm cleaner end 166 has a tip extension 168 which defines a pear shaped aperture 170 also known as a pear shaped scraper guide 170 this pear shaped scraper guide 170 provides additional control by providing a central pulling position and a variable offset for side pivot positions as the squeegee 100 is pulled down the length of the marker barrel the pear shaped scraper guide 170 guides the pin ears 208 of the cleaner head 198 to a central position in the barrel the friction of the.