Lost another HF bearing dust cover

Just got back from the High Sierras and was happy with the tear's performance but lost another dust cap. Last time I ordered another from Harbor Frieght but it was a bit pricey. Anyone know where to find a cheaper replacement and what size I need? It's for the HF 1800# and seems to be a hair over 2" diameter. Thanks, George.
http://img.photobucket.com/albums/v422/ ... 39_IMG.jpg
http://img.photobucket.com/albums/v422/ ... 39_IMG.jpg