This Very hard to find American Made standard diameter, 30 degree Curved glass downstem sleeve has an outside diameter of 12mil and inside diameter of 9.5mil. 3" 3.5" 4" 4.5" 5" 5.5" 6" 6.5" 7" Please choose length above. This item is custom made for us so may be slight variation in size. Can be used with both SHORT 8mil and 9mil sliders. Comes with rubber donut grommet. 12mil is approx 1/2" Because this item is Handmade. There may be slight variation in size. TIP:Use a little soapy water when sliding rubber grommet on to downstem. Please see Glass Accessories Measuring Guide.