All Categories > Sight Windows > W12 Series Non-ASME Sight Windows W12 Series Non-ASME Sight Windows Request Information W12 Series Non-ASME Sight Windows w12-series-non-asme-sight-windows W12 Series Style FP Flat Weld Pad Sight Windows W12 Series Style FP Flat Weld Pad Sight Windows (14) Benefits & FeaturesProvides direct visual observation of process in vesselsWelds directly to vessel7 Different Sizes (not specific pipe sizes)