A - The M-Rate is the mulching ratio - The higher the M-Rate the more the leaves will be shredded.
For example, a 10:1 ratio, such like the Scirocco - will reduce the leaves by 10 times their original size meaning you can collect 10 bags worth of leaves in 1 go. This figure is based on large leaves e.g. Sycamore, however some smaller leaves e.g. oak leaves may not be shredded. Using the mulching option on your garden blower vac allows you to collect more debris, with less trips to the bin!