Understanding how the umbrella works is an important step when developing a clear and concise comparison to buy the best product. 1. The canvas - This is the fabric that covers the accessory. The canvas is often made from polyester, a resistant material that does not degrade under the effect of the sun or rain. 2. The ferrule - This element is positioned at the top of the umbrella, between the mast and the canvas. Its role is to prevent water from flowing along the mast by sliding it on the canvas. For a better seal, one can also find a joint between the ferrule and the fabric. 3. The ribs - They support the canvas and guarantee better resistance of the umbrella. They also have an impact on the shape of the umbrella when it is open. 4. The slide - Whatever the type of umbrella (automatic or manual), the slide is the part which allows the umbrella to be opened or closed by a sliding action along the mast. 5. The mast - It is the spine of the umbrella which supports all the pieces.