The 46414 supply adapter is for connecting PEX supply lines to the Viega Manabloc or Viega Minibloc. The 53601 FIP end cap is for capping off one of the 3 inlet / outlets not in use on the Manabloc or Minibloc. Each Manabloc requires either 3 supply adapters or 2 supply adapters and one end cap that need to be purchased separately. Viega PureFlow provides the industry's most comprehensive selection of PEX tubing, fittings and accessories. Along with a wide variety of PEX fittings, which include both PEX Press and PEX Crimp, Viega also offers the patented MANABLOC water distribution system which helps homeowners realize a reduction in water waste and increased energy savings.