Standard: ANSI B16.5 Class:150, 300, 600, 900, 1500, 2500 Size: 1/2" - 24" Type: WN, SO, ... , Military, and so on..ANSI B16.5 FlangeClass:- 150, 300, 400, 600, 900, 1500, 2500Size:- 1/2" -24"Types: - Welding Neck (WN ... (MFM)Material used: - Alloy 20- Nickel 200, 201- Monel 400. K-500- Inconel 600, 601, 625, 718, 725, X-750, 751, 783 ...