Roboworm's Original 4 1/2" Straight Tail Worm. Robotic hand poured triple color worms, featuring Roboworm's exclusive "Salt Release System". Most worms have salt either trapped inside, or just coating the plastic. Roboworm infuses the head of the worm with salt allowing it to slowly leech out during your cast. When a fish bites, a burst of salt is released, causing the fish to hold on longer for a better catch ratio.