A reproduction of the AR-180 (civilian version of the AR-18), the 180B differs in few ways. It has a fixed stock instead of a side-folding stock, uses a polymer instead of stamped steel lower and will use and accept standard AR-15 magazines. The older AR-180 has it’s own mags but AR-15 mags could be modified to work in them.
Not sure if these reproductions are still in production. I haven’t seen new ones lately.