I used to use 661 pads for rockier sections or riding on unfamiliar stuff but they always used to fall down – they were the ‘comp knee/shin’
After a hard fall on my knee where my pad had completely dropped out of the way, I decided I needed something better.
I ended up going for the ‘Pro knee/shin’ also by 661.
I tried them on before buying and spent a long time walking around the shop in them, feigning a cycling motion etc. and they didn’t budge.
They are quite a bit bulkier than the ‘comp’ and have a velcro ‘sock’ that goes round your knee. The knee pad move independently to the sock and so doesn’t work itself down your leg.
Only thing with them is they are quite warm – although not as bad as I was expecting to be honest – and I wore them all day in Spain last year in July when it was touching 42 deg. C so they are by no means too hot.
Definitely worth a try I reckon.