I tested several backpacks for this and this one easily won. It’s comfortable, the sprayer fits in it perfectly, it has lots of pockets, and–so far–seems waterproof. I’ve put some very wet ropes into the pockets and so far nothing has bled through to other areas. It’s fully lined–even the pockets and it comes in 11 colors! Any backpack will probably work, but c’mon–this little number is sexy, right?!