Well established motorbike protection company Knox are entering the mountain bike market with this knee and shin pad combo.
First impressions weren't great - they look like elbow and arm guards. In use they redeem themselves a little. The hook and look fasteners hold everything very snug and don't snag clothing like velcro. Unfortunately these knee pads feel far more clunky and bulky than they look, and restrict movement quite a bit.
The shin pieces don't extend far enough down the leg to afford any protection from pedal slips, but do go low enough to interfere with your shin pads and reduce mobility.
While they are CE rated, protection is patchy. Hard plastic shells are great at stopping sharp points but the thin padding means that if you fall hard onto your knees there may not be enough shock arbsorbtion to protect them. Also, they only cover the front of your knee and (top of) lower leg.