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Description
Sierra 18-3721-9 Stainless Steel Locknut for Mercury & Mercruiser Engines - 5 Pk
Sierra high-quality engine parts are designed to meet OEM specifications. Stainless Steel locknuts with nylon inserts.
Thread Size: 7/16" or 11.1mm - 20
- For MCM inner transom studs and prop nut for Mercury 39, 60 (1968 & newer, 8 spline)
- For MR/Alpha engines
Interchangeable with:
- GLM
- 21170
- Mallory
- 9-72004
- 9-72004-10
- Mercruiser Stern Drive
- 11-29241
- 11-24648
- 11-21298
- 11-22178
- 11-82671015
- 11-33962
- 11-34933
- Mercury Marine
- 11-95702
- 11-46355
- 11-34933
- 11-82671015
- 11-22178
- 11-859116
- 11-134391
California Residents: 
WARNING Cancer and Reproductive Harm - P65Warnings.ca.gov
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