These 100 round dual drum AR magazines are the Generation II model of the drum we have carried for several years now. They have been improved by strengthening and reinforcing the feed lips and eliminating the need for a graphite lubricant. We have had super success with the other ones but we are told that these are even better. All have clear fronts for viewing remaining rounds as you fire. They're manufactured in South Korea for the Korean Military for use in their M16 rifles but work equally well in AR-15 rifles. Made to meet or exceed NATO Specs.