Product Item: Dual Plate Lug Check Valve, Metal Seat
Design Standard: API 594
Size: 4 Inch, DN100, 100 mm
Pressure Rating: Class 150 LB, PN20
Body Material: ASTM A216 WCB
Disc Material: ASTM A182 F316
Seat/Seal Material: ASTM A182 F316
End Connection: Lug Type

Source: https://www.landee.cn/dual-plate-lug-check-valve-api-594-a216-wcb-4-inch-cl150.html