Genuine Bosch Dust Extractor Port Light Sander Hose Adapter Attachment. This oval to round port adapter is designed for connecting light hoses to your sander. The outlet of the Bosch adapter is 29.5mm diameter with an O ring taking this up to 30.5mm. The round connector is 19mm diameter. This part is suitable for sanders which have an oval outlet, not a round outlet. Fits models: GEX125, GEX150 AC, GSS140, GSS280 AE, PBS7AE, PEX11, PEX12, PSM160A, PSS180.