The Thule Subterra Backpack 15 inches 23L is a useful 23-liter backpack for commuters. Do you carry a lot of stuff with you when you go out for a day? In that case, we recommend the larger 30-liter Subterra. You can protect your electronic devices, like your 15-inch laptop, from scratches and bumps, thanks to the padded inner compartments. Did you cycle to work fast ? Fortunately, the ventilation systems in the back panel ensures that the hot air can get away. Do you want to take the backpack with you on holiday? You can easily attach it to the back of your trolley suitcase with the smartsleeve.Note: the size of your laptop, like 15-inch or 17.3-inch, is the screen size, not your whole laptop. If your laptop has wide bezels around the screen, it's better to choose a laptop compartment that's a size bigger. That way you'll know for sure that your laptop fits.