Essick Air Products 1B5060000 Black Plastic Bottle Cap for 400- 600 And H12 Series
Fits models: H12-001, H12-300, H12-400, H12-600, H-12-001, H-12-300, H-12-400, H-12-600, 4161, 4261, 4262, 426-300, 426-700, 427-300, 4362, 436-300, 4371, 447-301, 447-401, 4963, 496-800, 4971, 497-300, 497-800, 696-100, 696-400, 697-400.