Sash Anti-lift Block

On some sliders, a short piece of track insert is installed over each sash in the top of the frame (some replacement double sliders).

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If the block is missing, the sash can easily be lifted out of the frame. Normally, when the block is in place, it resides over the sash when the window is closed and the sash must be moved to the opposite side to remove it (some replacement double sliders).

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