JD7823 Button Head Grease Fitting Coupler - Keep 'Em Crawling
Amazon.com: Lincoln LIN81458 Button Head Grease Coupler (1/8 in MNPT) (Non-Carb Compliant) : Automotive
Lube-Link Large Button Head Coupler w Quick Connect | Legacy Manufacturing | L23
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1/8"NPT Button Head Coupler for 5/8" Grease Fitting | Fastenal