Water Gremlin makes the finest split shot. Water Gremlin Green Gremlin Tin Split Shot is made from tin and will not cause lead poisoning in waterfowl. These are available in both "traditional" removable split shot and a "round" split shot.
The removable split shot can be pinched closed or open easily. The round shot tends to hang up less in the bottom of the stream or lake, but pliers or forceps are needed to remove it. The environmentally friendly split shot is about one half the weight of lead shot. These weights come in a round plastic selector.
Water Gremlin Green Gremlin Tin Split Shot Selectors are made in the U.S.A.