They are actually Type 63 mags which is a Chinese domestic made select-fire carbine that combined features of the SKS and AK. Made in huge numbers but largely unknown in the West. Mags work fine in semi-auto AKs, but lack a milled clearance for a full-auto AK's disconnector. Will lock the bolt back after the last round is fired. Neat mags, and one of my favorite for bench shooting.