9/16" (15mm) Smoothline Bolt Slot System Narrow 9/16" (15mm) face features a 1/4" (6mm) center regress for a contemporary appearance. Mitered design on cross tee and main runner intersections produces a clean, continuous slot. Intermediate and heavy duty load bearing capabilities. Special T-bolt fitting available to facilitate installation of partitions, projection screens, track lighting and signage. Compatible with many standard lay-in lighting fixtures and air handling equipment components.