If alpro could make a pair of pads that you could insert into a set of work trousers then I'd buy them, but as for those other ones they just don't sit right on my knee , and the straps don't last !
It would be nice for a pro to design a good pair of pads ,I have used a lot of different pads over the years and have never come across a pair that are good and last ,the only ones was what I used to get of the local miners they was very robust,but cannot get them down my way now all the pits have shut.