i have 661 and Race-Face dig…much prefur the Race-Face… they seem a snug fit…then agin i havent worn knee pads for some time this summer,,,ive been riding much longer rides lately in rediness for a recent challenge ive just completed and prefured not to ride the knee pads … (touches wood)- i havent fallen off in ages ! come winter time tho and they,ll be back on…(Race-Face)… 😉