Prima Tech's retractable Twist-Up Livestock Markers are used mainly for short-term markings on cattle, sheep and pigs. For a good, visible mark, apply to the upper back of the animal. Markings will last about 4 weeks on cattle and sheep and 1 to 2 weeks on pigs. The twist-up plastic holder and cap keep your hands and clothes clean and allow you to use the entire marker. The non-toxic sticks contain special waxes, paraffin oil and high-quality dyes.