PRACTICAL DESIGN: The bottom of the square cover can adjust the length of the rope, so that the bathtub cover is firmly attached to the bathtub, will not be blown away by the wind. PRACTICAL DESIGN: The bottom of the square cover can adjust the length of the rope, so that the bathtub cover is firmly attached to the bathtub, will not be blown away by the wind. WATERPROOF MATERIAL: This square bathtub cover is made of 210D Oxford material, which is impermeable, lightweight, and durable. Note: This cover cannot be used alone without an insulated hard shell underneath. MULTIPLE SIZES: The spa cover is available in seven sizes: 218x218x30cm, 224x224x30cm, 220x220x90cm. Fits most types and sizes of bathtub covers, you can measure your bathtub size before purchasing. COMPREHENSIVE PROTECTION: Square bathtub cover close to the bathtub, can prevent dust, leaves, and other debris into the bathtub, keep the bathtub clean, for good protection. PRACTICAL DESIGN: The bottom of the square bathtub cover can adjust the length of the rope, so that the bathtub cover is firmly attached to the bathtub, will not be blown away by the wind.