The storage jar is well made in general. The bottoms solid and the cap twists off . Twist as in one twist. This isn't completely air tight. As the cap and base don't seem to have a real seal. This would be. Excellent for storing a daily strains , viewing and organizing them . The Magnet part could be very helpful if you use them in a set . I wish they were air tight and the window was glass not easily scratched plastic.