Drilling spools made the connection between the wellhead equipment, the blowout preventers stack and choke and kill manifold.
Top and bottom flanges, according to API 6A: 21 1/4", 20 3/4", 16 3/4", 13 5/8", 11", 9", 7 1/16" Flange outlets, according to API 6A: 4 1/16", 3 1/8", 3 1/16", 2 9/16", 2 1/16" Maximum working pressure: 2000 psl (140 bar) to 15000psl (1050 bar)
