A device (1) for providing a fixing point for an insulated glass unit (3), the device having clamping blocks (22) to mount the device (1) though opposed panes of glass (5, 6) of the unit (3) and a spacer (10) with opposed faces (13, 14). At least one of the opposed faces (13, 14) having an annular groove (17, 18) for carrying sealant to seal against an associated one of the glass panes (5, 6) when the glass panes (5, 6) are tensioned together by the clamping blocks (22).