How much does this cost to the nearest dollar?

Canon Drop-in Filter Mount Adapter EF-EOS R with Circular Polarizing Filter
The new Canon standard mount Adapter allows for EF/EF-S lens compatibility with the new EOS R mirrorless Digital Camera system. Allows EF/EF-S Lens compatibility with the EOS R camera Drop-in filter Adapter allows use of circular polarizing Filters Dust- and water-resistant Exterior design matched to EF lenses Metal mount on both Lens and camera sides provides rugged flexibility Dimensions 2.9 x 2.9 x 0.9 inches, Weight 4.9 ounces, model number Rank Camera Lens Adapters & Converters 229, Available September 4, 2018, Manufacturer Canon Cameras US, Brand Canon, Material Plastic, Photo Filter Thread Size 1 Millimeters, Photo Filter Effect Type Polarizer, Water

Price is $299.00
Price: $299