My local sail shop has only has red and green telltales. Should I try to find some black ones.....is black easier to see through the sails or doesn't it matter?
Thanks, Doug
Black is easier to read through the sail. I tried the red and green ones once and did not like them...Dan
Depends on what color your sail is. 
I've always used the black ones, although sometimes it is hard to tell which side is which, especially when looking through a sail window.
For training my new crew (14 year old daughter) I used a black tell tale on the starboard side of the sail and a red one on the port side. That way when I can say in or out on the sheet and watch the effect on the change on the tell tale. On a white Hobie sails the red shows through good and the black very good.
And yes Rick's shop has the black ones.
Jack Kartz