Specification: diameter 200, 300, 400, 450, 500, 600, 800mm Material: SUS304 SUS316L Standard: DIN,ISO (cover,manhole cover Specification: 200,300,400,450,500,600,800mm Material: SUS304 SUS316L Standard: DIN,ISO Application: apply to stanless steel tank, to meet manhole cover and dustproof. the location is on liquid level(cover,manhole cover)