Zalando has started trading pre-owned, or second-hand, fashion items on its platform. The online retailer launched the service in Germany and Spain on Sept. 21, and will roll it out in Belgium, France, the Netherlands and Poland in October.

If successful in those markets, Zalando could expand the service to other countries where it is present. The e-tailer covers 17 markets.

The company indicated that interest in pre-owned fashion is “high and growing” especially among Millennials. The service will enable customers to buy pre-owned items and trade in “lightly worn” items, according to Torben Hansen, the company’s vice president for recommerce.

He claims that the offer does not exist at this “scale and with this level of convenience in the European market so far” and believes that the service “has the potential to completely change the way our customers think about and interact with pre-owned fashion.”

The items offered have to be “in like-new condition without visible signs of use” and customers can trade in up to 20 items per parcel, he pointed out. Users have to take a picture and add basic information such as category and brand. Offered items that were previously bought on Zalando automatically appear in the wardrobe section of the user’s account. Items bought elsewhere can be uploaded and added to the selection of items ready to be traded in.

Sellers can see the bids and accept, or decline, after which the items are sent to Zalando for quality check. As a settlement, users can chose to receive Zalando credits or have the money donated to the charities Red Cross or WeForest.

The company is testing the shipment of all pre-owned orders using plastic-free packaging and recycled materials.