H.A.C 1 is a spring device designed to improve the seal of a sash at the vertical side of a large top hung window.
It consists of an acetal moulding set and a pair of profile related spring steel components. The simple act of closing the window causes the unique H.A.C 1 device to assist the compression between sash and frame. It also allows the use of night vent locking positions when required.

FEATURES
- Increases weather performance on tall top hung sashes
- Saves call out costs to  leaking casement window
- One component fits all
- 1 set consists of 2 springs and 2 packers
- Available in White or Brown