The lowest and strongest (not the prettiest) ring I am aware off is the original Weaver with the wrap-over steel strap on top, they grip extremely well.
I like them too.
They are also really light, despite their ruggedness, and as well as that you can take them off by hand and when you put them back on, by pushing them firmly to butt up against the front of the slots, the scope will go back pretty close to zero too.
