ASC Chevy C/K Silverado or GMC Sierra Full Size Extended Cab Truck 1988-1998 Dual 12" Subwoofer Custom Fit Sub Box Speaker Enclosure Dimensions: Width 56-3/4" x Front Height 10" x Rear Height 6-1/4" x Depth 13-1/4" Install Location: Under Rear Seat Install Notes: Relocation or Removal of Jack is required Mounting Depth: 6-1/2 Inches Air Space: 0.95 Cubic Feet