Ahh... you have touched upon one of the great mysteries especially to the westerners here in Qatar. I have been here nearly 15 years and yet to walk comfortably into
a so-called hardware store and find reliable, consistent stock. Everytime I go I wish for the convenience of a Wal-Mart or Home Depot to browse through.
Good luck in your quest. Seek and ye shall find, but with great effort and time.