EcoStraw, 0.25 mlEcoStraw, 0. 25 ml EcoStraws feature a wick with a shorter inner wick section that absorbs 3 to 4% fewer sperm than the corresponding symmetrical wick of standard semen straws. Yield a larger number of semen straws per ejaculate because fewer sperm are lost in the wick Better use of valuable genetics without adding additional cost Ideal for overnight equilibration