These kits convert a Rally 110 or 210 power meter from one cleat system to another. The measuring spindle stays; only the body changes.
That is the practical advantage of the Rally design over a crank-based meter: one power meter can serve a road bike on Look KeO or SHIMANO SPD-SL through the winter and a gravel or mountain bike on SHIMANO SPD in the summer, without buying a second meter.
Choose the cleat system you are converting to. The Look KeO and SHIMANO SPD-SL bodies use a carbon-based design; SHIMANO SPD uses an all-metal body suited to off-road use.
