A 4ft LED tube in frosted cover version is designed to replace the traditional fluorescent tube that has the base G13. This T8 4ft 18W LED Tube Glass in 18W can retrofit the fluorescent tube fixture when there is no need to contain the ballast as this tube is designed for bypassing the ballast. This method of bypassing the ballast brings enough savings in energy as there is no loss in energy and when this tube works draws in power through an internal driver.         
Well, that was about base and energy-savings. What about soft lighting and how does this help me? -- you might ask.
To explain that better, let’s consider the difference between a clear 4ft LED tube and frosted 4ft LED tube.

4ft LED Tube Clear and 4ft LED Tube Frosted --  The difference!

* First things first, in 4ft LED tube with clear lens or cover, you can be able to see the LED chips but the same is not true for a 4ft LED tube with frosted cover.
* The white light emitted through a clear LED tube is more clearer, stronger and brighter than that emitted by the frosted LED tube.
* So, in applications (such as mines, tunnels etc.) and weather conditions, where fog, dust, mist may be an issue, such clear lighting can be of great help.
* By contrast, the 4ft frosted LED tube is great for applications such as indoor areas in home or office such as study rooms, living rooms, kitchen areas etc.
* This is because the light beam comes out of the frosted tube in the form of soft light and will be 30-40% less brighter than the clear tube.

The Last Word

What you choice out of the two is entirely your choice but always make a final choice based on what application you are going to use the 4ft 18W LED tube glass for.  
For more info: https://www.ledmyplace.com/products/t8-4ft-18w-led-tube-glass-5000k-frosted-single-ended-power-1-pack