Whenever I find something that works for mules and donkeys I like to share it with my friends. 

The RAMBO Fly Sheet is made in Ireland and stands up to the rigors of turnout..............even on my 16 hh mule Zorro.  The L fly mask actually fits Zorro's ears with a bit of room to spare.  My Quarter Horse, Dumpy, doesn't have enough ear to fill the M size.  This is the second one I've had.  The other lasted four years............on Zorro!  I got these these this year on sale for $129 and the fly mask was free.  I also us RAMBO Turn Out sheets and blankets. 

PROTECTS AGAINST FLIES, MOSQUITOES, DIRT, DEBRIS AND HARMFUL UV RAYS

http://www.horsetackco.com/index.php

Zorro is a mule who can totally destroy a blanket in 15 minutes.  But, he loves these fly sheets and almost jumps into fly mask.  He wore the other for four years.

Unfortunately, my Quarter Horse is ear challenged.

OOPS!  Going out right now to fasten the butt strap on Dumpy.  If you notice, the tail flap has a elastic piece through which you slip their tails (see how his tail lifts it?) so the tails get UV protection too.