3-3/4” Aperture New Construction. Mounting Frame: Accommodates all ceilings up to 1-1/2” thick. Junction Box: Through branch circuit conductors. Grid Ceiling installation: Tool free mounting in grid ceilings, interlocking side bars adjust to 24-1/8” long, adjustable speed clamps for positive attachment to grid ceilings. Wood Joist installation: Integral nail tabs, joist finder, fastener holes and bendable strapping guides for wood joist installation, interlocking slide bars adjust from 12-15/16” to 24-1/8” long to accommodate 16” and 24” O.C joist spacing, with or without strapping.