Water Gremlin developed the Rubbercor Sinker in 1949... the first truly original idea in sinkers since the rock. Rubbercor slips easily on and off your line. Just give the rubber ears a half twist in opposite directions and Rubbercor is ready to take your bait down to where the fish are biting. Your line is protected by the rubber core inside the lead sleeve. To remove, simply twist the ears back to their original positions. Theres no tying, no pinching, no fuss, no mess. Rubbercor is safe to use, even on the lightest monofilament line.