Abstract: A collapsible watertight assembly comprises an impermeable flexible container (1) having an open end adapted to be sealed, a neck (7) closable by a screw cap (8), and a roll and lock seal (9) which provides a watertight seal on the open end. The assembly further comprises a reticulated inner container (11) adapted to fit inside the impermeable container (1). In use, a person puts garments in the inner container (11), places the inner container (11) inside the impermeable flexible container (1), fills the impermeable flexible container (1) with water and a cleaning substance, seals the sealing means (9) and applies an agitating motion to the assembly to enable the garments to be washed. The assembly can be used as a portable laundry assembly, as a self-contained assembly for bleaching, dyeing rinsing and drip-drying clothes or to carry water or to keep items dry in high-humidity or damp conditions.