The APH Number Line Device is a tactile aid for math designed for use by students who are blind or have low vision. It has ten interchangeable vinyl line segments with black raised lines and dots at intervals. Forty plastic cylinders serve as pegs and/or interlocking bars. Numerals are in braille and print. The base allows two line segments to be used at once. DIMENSIONS (LxW): Base measures 6.5 x 24.5 inches.