This Pak-a-Pill™ 370 Series pill container was designed specifically to hold six nitroglycerin pills. They fit in such a fashion that they don't have room to jostle around and disintegrate. The container is fitted with two o-rings to insure that no moisture will penetrate the chamber. The second o-ring is also a safety feature which will not allow the cap to drop off if it were to accidentally get unscrewed. The cap is knurled for an easy grip, and it has the 'Quik Twist' thread design for a one turn open or close. Not only is this a very well made container, it is also a very attractive design. Highly polished finish.