I tried the grey knee pads first but the padding was to light for me. This black pare has the prefect amount of padding for me working normally on steel grading, all day doing scaffolding. I never used knee pads for 15 years because the knee pad would just slip down and annoy me, I gotta get stuff done.
Now with this knee pad, it's so comfortable and doesn't slip(once you find that sweet spot, fairly big threshold for that sweet spot too). I often forget I have them on and go to break with them on. I wear them all day(10-12hours a day).
Working conditions I'm in +35'C down to -35'C After a year the plastic did split a bit on the face of one knee pad but i'm still able to use them, the buckles and straps are still working great.