The Standard Hot Tub Cover has a thickness of 4" tapering down to 2". The Standard Hot Tub Cover is perfect for indoor or sheltered hot tubs. Weight: 30-35lbs Heat retention: Good Foam Density: 1.5lbs R Value: 16 4 Adjustable Locking Straps to meet ASTM safety standards. The Deluxe hot tub cover has a thickness of 5" tapering down to 3". The Deluxe Hot Tub Cover is the perfect cover for all seasons. Weight: 35-40lbs Heat retention: Better Foam Density: 1.5lbs (2lbs option available) R Value: 20 4 Adjustable Locking Straps to meet ASTM safety standards. The Premium Hot Tub Cover has a thickness of 6" tapering down to 4". The Premium Hot Tub Cover is perfect for harsh weather conditions. Weight: 40-45lbs Heat retention: Best Foam Density: 1.5lbs (2lbs option available) R Value: 24 4 Adjustable Locking Straps to meet ASTM safety standards.