This single sheath pouch from Maxpedition Hard Use Gear can carry extra items that don't fit in other packs. The fabric is abrasion and water resistant, so the contents stay dry and safe. The pouch can be worn at the waist or easily attached to a backpack.
Specifications and Features:
Durable single sheath
Can hold an extra flashlight, small cellular phone, multitool, folding knife, or handgun magazine
Can also be attached to your backpack as an accessory or be carried on the belt upright or sideways