Saddle bags are quite literally bags that fit to your bikes saddle. They vary in size, from tiny aerodynamic packs, holding a spare innertube and maybe a multi tool, all the way to heavy duty bike packing options to carry clothes, tents or just about anything for an epic ride. Features to look out for are waterproof fabrics, especially if you’re carrying a mobile phone, reflective trim to help with visibility and even a light loop to fix a rear light in place.