The Canon ET 63 Lens Hood is primarily designed to prevent unwanted stray light from entering the lens by extending and shading the end of the lens. In addition, since the end of the lens is extended, you also get the added benefit of some extra protection from accidental impact. The ET 63 lens hood is specifically designed to attach to the end of the Canon EF S 55 250 f4 5.6 IS STM Lens.
Price: £12.99 from Wex Photographic
The Canon ET 120B Lens Hood is for use with the Canon EF 200 f2L IS USM lens and will protect your lens from dust and scratches.
Canon ET 73B Lens Hood is for use with the Canon EF 70 300mm f4 5.6L IS USM lens and will protect your lens from dust and scratches.
The Canon EW 65B Lens Hood is for use with the Canon EF 24mm28mm f2.8 IS USM lens and will reduce glare and lens flare as well as helping protect your lens from dust and scratches.