USD421820SExpiredUtility

Protective respiratory helmet with rear recess design

56
Assignee: 3M INNOVATIVE PROPERTIES COPriority: Mar 10, 1998Filed: Mar 10, 1998Granted: Mar 21, 2000
Est. expiryMar 10, 2018(expired)· nominal 20-yr term from priority
Inventors:Brett R. Johnson
56
PatentIndex Score
9
Cited by
10
References
1
Claims

Claims

exact text as granted — not AI-modified
The ornamental design for a protective respiratory helmet with rear recess design, as shown and described.

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