So you're specifically wanting the one with the ring and the two ends that "bite" into the ring then?
The problem with those exact finials and the loop, as I reacall it, is you have two choices: You either get a longer chain that you can pull over your head, or you get a shorter chain that is on you permanently. The deal is, you buy the chain and the Mjöllner, then the manufacturer puts the Mjöllner on the loop then ties the look and the two finials togehter for good. It is an actual knot. Once you're in a short chain, you're in it and you can't get it off w/o cutting it off. Or you can get the longer version, so you can take the whole assembly off, but with each 5 cms of handknotted silver thread added, the price of the piece goes up exponentially. That's another reason I'd not recommend buying it mail order - you sort of have to be there when they guy makes it. If the chain is too long, the Mjöllner ends up sitting on you wrong, too. Since I didn't have my husband with me at the time, I opted for another chain in the end, but it doesn't have that loop thing in your picture. It isn't actually a loop up close, but more of a triangle, because it has to be adjusted to fit the Mjöllner, too. The top part of the Mjöllner is like a straw, so it can't accomodate a circle. It is all ties together, but it pretty much has to be done by a silver smith. That's according to the guy that makes them, who said I could buy all the parts from him, but once I had my hubby with me, we'd have to go to a Canadaian silver smith for him to make the loop-thingy and knot it in place. Kind of hard to explain.
You might be able to get something that suits you, I just wasn't able to, but I ralize that's partially because I have a husband with a big chest. I've been searching for a huge ass hammer that doesn't look like a speck on him for a few years now, and so, I needed a chain that could accomodate such a large hammer. I litterally bought the biggest Mjöllnir on all of Gotland, and it's also very thick, almost 1 cm thickness. You can't just do a pretty little chain with a hammer like that. The same goes for Johan - he's a big tall guy, and regular hammers look like fly shit on him. He needs a chain and a hammer with some size to it.
I can see if I can dig up the addy for that dude's store that did Johan's, but guaranteed, it'll cost you a shit load.