We completely redesigned B-20U handguards for RPK-based rifles: they became lighter, more ergonomic and are made in two modifications now depending on mounting seat.
Seats on different shotguns may vary, so before buying, check the appearance of your regular handguard. Two types are possible: Type A with a wider seat and Type B with a narrower seat. Type A corresponds to B-20U V.2.0 handguard, Type B - to B-20U V.2.1 handguard. 
More information about how to choose correct modification - on B-20U product page.
We also introduce one more new product: B-19RPK upper handguard that is compatible with B-20U gen two.
Those products are already available!