endura product is the best.
these work super well, & are comfortable to boot.
661 knee pads fit fine w/ them.
sizing runs on the small size, so get 1 size up.
don't try & use the liner snap-in system as it will un-snap during ride depending on how much you move around on your bike. there's really no need for the liner to coordinate w/ the shell anyway, as both stay put.
the plastic belt is a bit cheap, but isn't a game changer either.
the knee articulations are well designed as is the overall shape & all fabrics, per panel.