26H Ringed shakers, prairie green glaze. S7/P7 double diamond hole set, red clay. In 1970 Frankoma switched from using American rutile to Australian rutile to make the variable glazes like prairie green, desert gold, brown satin, etc. This is the low contrast post-1970 version of prairie green. The clay is still red so this set is pre-1974. Those factors indicate a date of manufacture between 1970 and 1974. The bottoms should, however, be glazed if all of my theories hold. I guess there are exceptions to every rule!