J.C. Whitney, $12.99

http://www.jcwhitney.com/autoparts/Product/Pr-p_Product.CATENTRY_ID:2004477/c-10101/Nty-1/p-2004477/Ntx-mode+matchallpartial/N-10101/tf-Browse/s-10101/Ntk-AllTextSearchGroup?Ntt=light+convertor

Autozone, $11.99

http://www.autozone.com/R,NONAPP10072/store,1647/shopping/accessoryProductDetail.htm

O'Reilly Auto, $16.49

http://www.oreillyauto.com/EW3/ProductDetail.do?id=356734710&line=HOP&itemNumber=48925&toolsAccMoreIndex=View%20All%20Matches&didSearchFor=Light+Converter&bid=1205877070996&cycleCount=854&currentPage=0