Based on the results, the Nike Elemental Backpack - Ns in grey for R519 would be an excellent choice. As one of the top hits specifically mentioning "grey", it matches your requested color while providing the quality and style you expect from Nike. Let me know if you would like any other details on this backpack. I'm afraid the search results did not contain any images, but I'm happy to try searching further on PriceCheck to find more options in your preferred gray color. Please feel free to provide any other details you may need to find the perfect backpack.
