I have a Wahl 9307A that came with no guards, so I designed these.

My Wahl hair trimmers came with 9307A as an extra little trimmer, but it must have been meant to edge things only as it didn't come with any length guards. I wanted to use it on my beard so I designed this set of guards ranging from 3mm-10mm. They are model specific, but perhaps will be of use to someone else out there. For putting them on, start at the back and then clip in the sides.