The Vent-a-matic aperture adaptor enables you to fit 105, 106, JG, C106S, DGS106, PBS, and PB Vent-a-matic vents into existing apertures of ø 180 mm to 200 mm. Sold in a pack of 2, one aperture adaptor is placed on each side of the glass with the 1 mm projection fitting into the hole.