EXHIBIT 22.1

List of Subsidiary Guarantors and Affiliates Whose Securities Collateralize

Securities of Nine Energy Service, Inc.

Each of the subsidiaries of the Company listed in the table below (each, a “Subsidiary Guarantor”) is a guarantor of the Company’s 13.000% Senior Secured Notes due 2028 (the “Notes”), and the equity interests of each Subsidiary Guarantor have been pledged as collateral for the Notes and the guarantees thereof.

Name	State or Other Jurisdiction of Incorporation or Organization
CDK Perforating, LLC	Texas
Crest Pumping Technologies, LLC	Delaware
Magnum Oil Tools GP, LLC	Texas
Magnum Oil Tools International, LTD	Texas
MOTI Holdco, LLC	Delaware
Nine Downhole Technologies, LLC	Delaware
Nine Energy Service, LLC	Delaware
RedZone Coil Tubing, LLC	Texas