i orderd a set of the st1 17mm and they are the cheapest i have found . the ofna set with the nut and the hex are more for the same thing , i guess you pay for the annodizing blue color.
st1 set
http://www.amainhobbies.com/product_...oducts_id/2607
ofna set and you only get 2[:@]
http://www3.towerhobbies.com/cgi-bin...?&I=LXCBA4&P=X