PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

9520-21-1Seat,valve

The Walworth Company · NSN 4820-00-308-9890 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-00-308-9890 — this item is cataloged by the U.S. Government under National Stock Number 4820-00-308-9890. Primary manufacturer part number: 9520-21-1.
Features
  • Seat,valve — FSC 4820
  • Seat Angle in Deg: 12.000 NOMINAL
  • Seating Surface Shape: ANGULAR
  • Surface Treatment: ANODIZE OVERALL
  • Material: STEEL OVERALL
  • Body Outside Diameter: 4.182 INCHES NOMINAL IN
  • Body Inside Diameter: 3.700 INCHES NOMINAL IN
  • Style Designator: PLAIN
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
  • Applications requiring Steel Overall construction
General Description

The Seat,valve, cataloged under National Stock Number 4820-00-308-9890, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is The Walworth Company. Government technical data includes 7 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 4 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 1 verified substitute exists in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN4820-00-308-9890
Primary Part Number9520-21-1
Item NameSeat,valve
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerThe Walworth Company
StatusCANCELLED
Seat Angle in Deg12.000 NOMINAL
Seating Surface ShapeANGULAR
Surface TreatmentANODIZE OVERALL
MaterialSTEEL OVERALL
Body Outside Diameter4.182 INCHES NOMINAL IN
Body Inside Diameter3.700 INCHES NOMINAL IN
Style DesignatorPLAIN
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 1
5330-01-119-4403 INTERCHANGEABLE
Gasket
Cross-Reference Index
Part NumberManufacturer
9520-21-1 PRIMARY The Walworth Company (USA)
F3191930ASL2PC5 Naval Ship Systems Command (USA)
N10915SL2PC5 Walworth Co the (USA)
9520-21-1 Walworth Co the (USA)
Related Parts
5330-01-119-4403INTERCHANGEABLE
GASKET

Frequently Asked Questions

What is NSN 4820-00-308-9890?

NSN 4820-00-308-9890 is a Seat,valve, manufactured by The Walworth Company, classified under FSC 4820 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 4820-00-308-9890?

NSN 4820-00-308-9890 has 4 cross-referenced part numbers: 9520-21-1 (The Walworth Company), F3191930ASL2PC5 (Naval Ship Systems Command), N10915SL2PC5 (Walworth Co the), 9520-21-1 (Walworth Co the).

What NSN replaces 4820-00-308-9890?

There is 1 known substitute for 4820-00-308-9890: 5330-01-119-4403. Verify interchangeability with system specifications before substitution.

What are the specifications of 9520-21-1?

Key specifications for 9520-21-1: Seat Angle in Deg: 12.000 NOMINAL; Seating Surface Shape: ANGULAR; Surface Treatment: ANODIZE OVERALL; Material: STEEL OVERALL. 8 total characteristics are documented in the Federal Logistics Information System.

Is NSN 4820-00-308-9890 still in active supply?

NSN 4820-00-308-9890 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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