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Exhibit 21.1
Subsidiaries of NPK International Inc.
December 31, 2025
DBM SERVICIOS, S.A. de C.V.
DURA-BASE DE MEXICO S.A. DE C.V.
DURA-BASE NEVADA, INC.
GRASSFORM PLANT HIRE LIMITED
NEWPARK CHILE LIMITADA
NPK BRASIL LTDA
NPK TEXAS LLC
NPK ACCESS SOLUTIONS LLC
NPK ACCESS SOLUTIONS (UK) LLC
10 NPK ENVIRONMENTAL WATER SOLUTIONS LLC
11 NPK HOLDINGS LLC
12 NPK INTERNATIONAL REAL ESTATE HOLDING LLC
13 NPK LATIN AMERICA HOLDING LLC
14 NPK MINERAL GRINDING LLC
15 NPK PERSONNEL SERVICES LLC