What do the arrows on the saw blade indicate?

Obviously I don't know because I put it on backwards. My first time
cutting aluminium (working on a deck project and need to trim the spindles)
and it took forever to cut. Flipped the blade around and now it cuts
wonderfully.

Any suggestions for a blade lubricant for cutting aluminum? Paraffin needs
to be reapplied about every 3-4 cuts. I'm using an aluminium cutting blade
in my CMS.

Puckdropper
--
Make it to fit, don't make it fit.