These are Anodized Heavy Duty Stackers designed by Andy Renzetti and Pat Ehlers of Wisconsin. These are ideal for stacking hair bugs, large amounts of hair for large flies and streamers. Heavy aluminum base with wide barrel tubes. Really nice with a great price for the quality. Made in USA. Bottoms are rubber coated. Standard is great for muddlers while the magnum is ideal for streamers, bass bugs or saltwater bucktails. Standard is 5/8” by 1 3/4”. Magnum is 3/4” x 2 1/4”.