The shimano spd sh51 cleats are replacement or spare spd single release cleats that works with all shimano mountain bike spd pedals except the ppdm858 the cleats are easy to install on to your pedal and is ideal to have as a spare around your bike workshop just in case you need to freshen up your bike pedal the spare cleats are easy to use once installed on your bike all you simply do is twist your heel outwards to remove your foot from the shimano cleat making it easy and simple to use and