I use these except the picture is for places where they drive on the wrong side of the road . . Just rotate and it works for either bifter
I have also used "Mirrycle" mirrors, and attach directly to Shimano STI shifters. like Doug64 has a picture of . It is a better mirror surface

http://www.google.com/products/catalog?q=blackburn+bicycle+mirror&hl=en&prmd=imvns&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&biw=1600&bih= 799&um=1&ie=UTF-8&tbm=shop&cid=17855534723108696587&sa=X&ei=tqnQT_qEI-Te2QWPy9ysDA&ved=0CG8Q8wIwAA