Webstone’s Hydro-Core Double Ball Drain is a new hydronic manifold designed specifically to ease the installation of mod/con boilers with internal pumps. It fits 40 different boilers from 15 different manufacturers. Designed specifically for hydraulic separation and purging the near-boiler piping or secondary circuit loops, it is guaranteed to save you time, space and leak paths. www.webstonevalves.com/literature.html.