The sure stop turns off your electric Downriggers auto stop at the same spot every time. The tuna cord provides a secure hold for your self-locating snap and is easier on your hands when pulling your gear to the boat. Tubing has been added to provide protection against abrasion in high wear areas.377-378: The stainless steel split ring prevents your 3025 weight retriever from sliding off your cable (3025 sold separately). The Scotty Snubber absorbs shock, provides electrical insulation and helps prevent snags.