These are known as Prismatic Diffusers and their job is to spread light evenly. They also hide the fluorescent tube from view if you don’t fancy staring at it!
Popular applications are in domestic kitchens, offices and schools (where they protect pupils from falling glass if the tube is broken!)
They can be retro fitted, that is fitted to existing fluorescent fittings by attaching them to the original cover plate screws. They do tend to yellow with age, they can also become quite brittle as the uv in the fluorescent does affect them over time so replacing them with new ones is a simple way of brightening up a room.
They are available for both single and twin light fittings.
They can only be ordered in pairs as shipping them singly is very difficult!
If you have the square Prismatic Panel light fitting then we also have those. If you are looking to save energy or your fittings need replacing we would definitely recommend upgrading the the very popular LED Panel which will save you a lot of energy but not reduce the level or quality of light.