The Zebra Barracuda ZS Twist: one bundle of counter–clockwise twisted strands (the "Z" strands) ... the other bundle of clockwise twisted strands (the "S" strands) ... twisted together to form a single, balanced bowstring!
Single–bundle bowstring (unbalanced): Alignment device can affect shooting consistency by adding even torque to the bowstring. A single bundle bowstring rotates as you draw and requires rubber tubing to assure peep alignment.
Dual–bundle bowstring (balanced): No peep sight alignment device necessary. The Zebra ZS Twist dual bundle bowstring is balanced — it will not rotate as you draw.