Markal Silver Streak Red Riter Holder Scissors & Snips Fixed Blade Knives Size Age weight Calf Circumference Small Tools Measuring Tapes & Reels Size Age weight Calf Circumference Small 4 7 Year Old Person 6 to 9 inch circumference calves Medium 50 110 Pound Person 9 to 14 inch circumference calves Large 110 200 Pound Person 14 to 18 inch circumference calves X Large 180 250 Pound Person 18 to 23 inch circumference calves XX Large 250 350 Pound Person 23 to 30 inch circumference calves XXX Large 350 500 Pound Person 30 to 36 inch circumference calves Solid Color Snake Guardz snake gaiters are FR and are tagged as follows: For use on almost all surfaces Markal Silver Streak Red Riter Holders are specially designed to help fine line marking during metal layout and fabrication The Markal Silver Streak Red Riter Holder is a tough metal holder for flat Silver Streak and Red Riter welding markers