No, this extension is for the uniform-color Hue Lightstrip Plus (https://www.digitec.ch/en/s1/product/philips-hue-lightstrips-basis-bt-rgbw-200-cm-led-strips-13274601).

If you have the Hue Gradient Ambiance Lightstrip (https://www.digitec.ch/en/s1/product/philips-hue-gradient-ambiance-basis-multicoloured-200-cm-led-strips-16467480), you need the Hue Gradient Ambiance extension(s):
Philips Hue Gradient Ambiance Erweiterung (Multicoloured, 100 cm)

Note you can extend it up to 10m, and the gradient segments will get reconfigured for the new length on power-on. This means if you want to run them all around a room for example, you may want to use separate base modules for each wall if you want more control over their colors.