Yes, these are the top latches on my Novara 'Round Town grocery-bag panniers (from REI). Very solid. Made by Rixen & Kaul. The mounting plate (shown on the same page) is also used on mine (one per hook).

These would be an elegant and inexpensive way to convert a pair of military surplus "musette bags" (or similar) to what I consider "everyday" panniers: not for multi-day/extended touring, nor for shlepping purchases home; rather, for carrying extra water, food, clothing, etc. when out for a half/full-day ride. Or, so I theorize... it's what I'm planning to do: find a pair @$15/each, spend another $15-$20 for hardware, and hook 'em up to my Pletscher "Inova" rack. I've looked at the major (and minor) players, and their panniers are too big and too expensive... "too big to 'rail'", so rolling my own seems feasible.