AGRI-PRO Economical, reusable semi-disposable balling guns made of durable plastic: Blue: Smaller boluses for calves, lambs and colts (0.475 diameter ribbed head). White: Medium-sized boluses for larger calves and sheep (0.570 diameter head). Red: Large boluses for feedlot and dairy animals (0.967 diameter head). F15-D-8 Small (Blue) F15-D8-1$1.85 Medium (White) F15-D8-2$1.85 Large (Red) F15-D8-3$2.19 Questions? Call toll free 1-800-892-6978 or email us at info@animalhealthusa.com