The backpack has pockets for a camera with a zoom, 3-6 additional lenses, batteries, and flashes. There is even a compartment for a small tripod and two pockets for SD cards. For various personal items, there's a big pocket on the top.
If you plan to go on long trips with your backpack, the Lowepro Slingshot may not be the best option. Carrying a lot of weight for a long time on just one strap will put a lot of strain on your shoulder.
For those who take photos regularly and have a lot of different accessories that you need to carry around, this might not be the best choice. You will probably need a backpack that is bigger, has more customization possibilities on the inside, and has some protection against harsh weather.