I don't know.

Hello Martin, I can't answer that for you. It doesn't work with the Kärcher extension set. Only the cordless window squeegee is attached to it. I first use an UNGER window washer with extension and UNGER's Liquid and then the Kärcher window cleaner (WV6). Also works at 3m! VG Klaus

The extension is compatible with all Kärcher window vacuum cleaners, including the WV series. However, there is no specific mention of the WV7 Signature Line in the information available. Therefore, I cannot say with certainty whether it is specifically compatible with the WV7 Signature Line. It would be advisable to consult the official Kärcher website or customer service for definitive confirmation.

The telescopic extension pole for the Kärcher Window Vac is extendible from 0.6 to 1.5 metres (approximately 2 to 4.9 feet).

Hello Patrick, https://www.kaercher.com/de/zubehoer/verlaengerungsset-26331440.html It says: "Compatible with all window vacuums and the vibrating battery-powered wiper" valid for order number: 2.633-144.0 I'm not surprised, because the extension is attached to the handle of the window cleaner with clips and an elastic loop.

According to the Kärcher website, the extension is compatible with all Kärcher window cleaners. However, as I have not used it yet, I cannot give any information from my own experience:-(