These inserts allow you to fire and eject .410 ammo through your 20 gauge double. They work fine with most O/U and SxS shotguns. This is a complete set including storage tubes, o-rings and brass removal tool! Condition is good, there is some staining on the outside of the tubes but no corrosion or pitting. I suggest AA ammo, a couple wraps of plumbers tape over the o-ring and tighter chokes for optimum performance. I have two sets and am keeping one. Increasingly hard to find and offered at only$175 shipped, paypal friend & family OK. PM OK, or email at steveziv@verizon.net.