H3578 Size: 6 lbs Features: -Window sash balance. -All steel construction coil spring retraction. -Aircraft cable lifters. -Replaces Duplex, Superior, Preset and Fabco. Specifications: -Size 4.5 lbs: 0.87"H x 3.37" W x 7.62" D. -Size 6 lbs: 0.87"H x 3.37" W x 7.62" D. -Size 8 lbs: 0.87"H x 3.37" W x 7.62" D. -Size 10 lbs: 0.87"H x 3.37" W x 7.62" D. -Size 12 lbs: 0.87"H x 3.37" W x 7.62" D. h3577 Installation h3578 Installation h3579 Installation h3580 Installation h3630 Installation