are these apple brand or off brand and if so are they certified
These are Apple product in OEM/bulk packaging.
This is the older Apple power adaptor. The Apple Store now only sells the 12W version. 3 of the 13 reviews on Amazon complain that it charges slowly. http://www.amazon.com/Apple-A1357-Power-Adapter-iPhone/product-reviews/B00DEDGGR6/ref=cm_cr_pr_paging_btm_next_2?ie=UTF8&showViewpoints=1&sortBy=bySubmissionDateDescending&pageNumber=2