Tack buttons (or bachelor buttons or dungaree buttons) are best described as the button used on Levi-brand jeans. It attaches like a snap with tension but is typically used in conjunction with a buttonhole. Tack buttons bachelor buttons and dungaree buttons are interchangeable.
Button-Fly Kit for Jeans – Core Fabrics
Jean Buttons, Hobby Lobby
Dritz Petite Press Portable Mini Iron - Yahoo Shopping
Jean Buttons, 6 pc, Antique brass — Prym Consumer USA Inc.
Dritz 4-65 Jean Buttons 11/16-Inch, Nickel, 6 Count
Nurse Buttons
Button-Fly Kit for Jeans – Core Fabrics
Fasteners - Sewing & Fabric - Category
Button Attacher
Buttons, Snaps, & Fasteners – Riverside Fabrics