Insulation supports secure batt-type insulation in place between joists. Use IS16 for joist spaced 16˝ O.C. and IS24 for 24˝ O.C. spacing. Position insulation batt in place between joists. Hold IS unit at the center and push into place. Wear gloves and safety glasses during installation. Joist spacing 16″ O.C.. Overall length: 15-1/2″. Code ref.: 120.