Abstract: A backpack (10) suitable for use with wheels (200) at its base adjacent to a non body-contact side (40) has a U-shaped opening (22) proximate to a body-contact side (30) that is closed with a zipper (31). The body-contact side (30) is provided with two shoulder straps (34) and a hip belt (36). Side straps (130) and a top flap or strap (134) connect the body-contact side (30) to other parts of the backpack (10), such as the non body-contact side (40), to take a substantial part of the weight of the backpack (10) and its contents so that the zipper (31) is not stressed or tensioned when the backpack (10) is worn on the back of a user. The wheels (200) are removable and can be larger than is usual for use on rough ground. A frame (100) with a built-in extending handle system (120) is mounted inside and ajacent to the non body-contact side (40).