PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

505-055Breech Ring,diver's Helmet

Kirby Morgan Dive Systems Inc · NSN 4220-01-237-3251 · FSC 4220 · No Item Name Available
Verified by PartsTable
NSN 4220-01-237-3251 — this item is cataloged by the U.S. Government under National Stock Number 4220-01-237-3251. Primary manufacturer part number: 505-055.
Features
  • Breech Ring,diver's Helmet — FSC 4220
  • Shape: OVAL
  • Criticality Code Justification: AGAV
  • 3 verified cross-references
  • Primary manufacturer: Kirby Morgan Dive Systems Inc
Applications
  • Industrial maintenance and repair
  • Government and military logistics
  • Equipment overhaul and refurbishment
General Description

The Breech Ring,diver's Helmet, cataloged under National Stock Number 4220-01-237-3251, is classified within Federal Supply Class 4220 (No Item Name Available) of the Fire Fighting, Rescue, and Safety Equipment group. The primary manufacturer of record is Kirby Morgan Dive Systems Inc. Government technical data includes 2 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 3 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 5 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4220-01-237-3251
Primary Part Number505-055
Item NameBreech Ring,diver's Helmet
FSC / FSG4220 / 42 — No Item Name Available
ManufacturerKirby Morgan Dive Systems Inc
StatusACTIVE
ShapeOVAL
Criticality Code JustificationAGAV
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 5
4140-00-120-1203505003 INTERCHANGEABLE
Blower Assy,centr
Rbc Transport Dynamics Corp Div Rbc Transport Dynamics
1610-00-547-6066505055 INTERCHANGEABLE
Plate,pitch Lock Fl
Hamilton Sundstrand Corporation Dba Collins Aerospace
5930-00-578-4265505003 INTERCHANGEABLE
Switch,lever
Mason Electric Co. Dba Mason Controls
5895-01-508-5433 INTERCHANGEABLE
Indicator Group
2920-01-651-1383 INTERCHANGEABLE
Terminal Block,electrical
Cross-Reference Index
Part NumberManufacturer
505-055 PRIMARY Kirby Morgan Dive Systems Inc (USA)
505-003 Kirby Morgan Dive Systems Inc (USA)
592-6318245 Naval Sea Systems Command (USA)
Related Parts
4140-00-120-1203INTERCHANGEABLE
BLOWER ASSY,CENTR
505003
1610-00-547-6066INTERCHANGEABLE
PLATE,PITCH LOCK FL
505055
5930-00-578-4265INTERCHANGEABLE
SWITCH,LEVER
505003
5895-01-508-5433INTERCHANGEABLE
INDICATOR GROUP
2920-01-651-1383INTERCHANGEABLE
TERMINAL BLOCK,ELECTRICAL

Frequently Asked Questions

What is NSN 4220-01-237-3251?

NSN 4220-01-237-3251 is a Breech Ring,diver's Helmet, manufactured by Kirby Morgan Dive Systems Inc, classified under FSC 4220 (No Item Name Available). Status: active.

What are the part numbers for NSN 4220-01-237-3251?

NSN 4220-01-237-3251 has 3 cross-referenced part numbers: 505-055 (Kirby Morgan Dive Systems Inc), 505-003 (Kirby Morgan Dive Systems Inc), 592-6318245 (Naval Sea Systems Command).

What NSN replaces 4220-01-237-3251?

There are 5 known substitutes for 4220-01-237-3251: 4140-00-120-1203, 1610-00-547-6066, 5930-00-578-4265 and 2 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 505-055?

Key specifications for 505-055: Shape: OVAL; Criticality Code Justification: AGAV; Special Features: NECK CLAMP PART OF 6318240-1 YOKE ASSEMBLY; End Item Identification: UBA MK 21 MOD 1 HELMET ASSEMBLY 6318360. 4 total characteristics are documented in the Federal Logistics Information System.

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