This is the reversible Ruger 22lr BX25x2 mag for the 10/22 rifle. Basically, it's two BX25 mags welded together for a pair of reversible 25rd mags. It's a monstrous contraption that performs quite well. Hard to get right now, and MSRP is right around $70 if you can find them below the stoopid $100+ panic prices. $80 PayPal will have it delivered to your door in 2-4 days. New in plastic. First "I'll take it" PM gets it.