1001730 Round flat glasses 2mm thick, with centre hole drilled (4mm). From 7 3/4" to 8 3/8" diameter (approx sizes only) designed for mercury wheel barometers and to be plaster of Paris fitted from reverse of bezel. Not for aneroid barometers which generally require a thicker glass bevelled and snap fitted from the front - THIS IS NOT FOR ANEROID BAROMETERS
