Lots of B&T shops on the Island have them. I would hope stores by you would also. I am not familiar with the chains you are mentioning. I have seem them with different arrangements. All of them usually have two small rings on either side for line attachment. Some have a barrel swivel on one side, some have snap locks on one side, and some have what looks like silver ball bearings from one or both sides.
I use these often especially for stripers. There is one thing you should be carefull of however. If you tie your line directly to the rings that are "IN" the lead you can lose a fish. The lead tends to be rough, edgey, and sharp...good enough to cut through line. I use a snap swivel at the terminal end of my line and connect with that. The barrel end of the drail I attach to my leader.
Some guys don't like any xtra terminal tackle. they feel it is something else that can break or that a fish may see it more. I feel that if the leader is long enough it should not matter and that if you tie it directly to the drail you will lose a fish eventually.
P.S. I have not seen drails over 3 ounces, does anyone know if they make them larger.
Some people refer to these as bananna drails, sinkers, weights, ect. But they do also come in a somewhat cylindrical shape fat in the middle and tapered at the ends.