Sharpie Precision Ultra-Fine Permanent Markers Black 2/Pk 37161 Ultrafine Brand: Sharpie Purchase is for one pack of markers 2 Ct/Pk. MADE IN THE USA The ultimate precision tip let's you get right to the point—extra precise narrowed tip for extreme control and accuracy. Durable tip marks permanently on most surfaces. • Extra precise, 0.2mm narrowed tip for extreme control and accuracy. • Color: Black • Permanent on most surfaces. • Fast drying, fade and water-resistant ink • AP Certified nontoxic • Pack of 2 Markers • 7.6 x 4.3 x 0.5 inches • Shipping weight 2 ounces • UPC: 071641371613 • MPN: 37161 • • Reviews: • • These markers seem to last a long time if you take care to cap them as soon as you are finished with them. You also need to be careful not to get the tips wet or to damage the tip, but as long as you do not drop the pen on its tip it is reasonably durable. We have tried a lot of different pens and markers for writing on plastic, and have had limited success. Many pens seem to take forever to dry or will not mark on plastic. So far Sharpie permanent fine-point and ultra fine-point markers avoid these problems, and provide sharp print for nearly all labeling needs. In fact, I will warn you that you should take care what you write on, because once you have used the Sharpie, it can be nearly impossible to get the ink out.