Striker Calf RopeRattler Rope Company 28' Smooth 4 Strand The first four strand calf rope with a core; the Striker is the most consistent calf rope available. It is constructed of a special synthetic, industrial strength polyester that will not stretch, giving it a longer life and more consistency. The four strands give the Striker a smoother, faster feel than a polygrass. The CoreTech core stabilizes the Striker, allowing it to rebound to its natural state.