Each of these rings would be considered a 3-stone bypass ring. The writing inside the rings might tell you more about the metal (i.e., the purity if it's gold - 9ct, 10ct, 14ct, 18ct... or silver -.925). The writing might also indicate the carat weight of the stones, if they're diamonds.
Beyond that, there's not much I could tell you even with better images. A very clear image of the diamonds might give a hint to the age of the rings, if the diamonds are old mine cuts, old european cuts, or transitional cuts. My strictly off-the-cuff guesstimate is that the center diamonds are in the 10 to 15 point range (.10 to .15 carats) at most... maybe up to 20 points but I doubt that. But - the pictures are not clear and there's no real point of reference for the overall size of each ring, so you might be pleasantly surprised when a real expert has a chance to see these rings in person.
Value-wise, you probably won't be able to sell them for much more than scrap value of the metal. The diamonds are not likely to add much value since 1) there will be a cost associated with removing or recovering the diamonds that would offset the value of the smaller diamonds, and 2) if diamonds reflect wear and damage comparable to what we see in the setting, even the larger diamonds won't be worth that much.
The greatest value of these rings will likely be their sentimental value. The very utilitarian styling, combined with the amount of wear these rings show, make me think that there's probably quite a story of love, hard work, and perseverance behind them.
By the way, I find it fascinating that you have two such similar rings. Do you know if they were originally owned by the same person?