Hello JuliaA849, thank you for your question. The Solo breast pump is only suitable for single-sided pumping. It is not possible to use the Solo breast pump with a double pump set for double-sided pumping. However, you can convert the tube of the HF double pump set (insert the Y-part on one side) so that it is possible to use only one Hands-Free cup and you can pump Hands-Free on one side with your Solo breast pump and this set. All the best, Medela Schweiz AG