FCS Nubster Fin Adding this to the center of a quad's center twin fins increases hold. Recently, it's also been used in a Nubster set with Kelly's Ender fin twin fins. Recommended for twin fin enthusiasts. When used in powerful waves, it provides hold at the bottom, almost like a twin fin, while maintaining the unique acceleration of a twin. This allows you to ride through hollow and fast waves. Highly recommended for twin fin lovers who dislike the feel of a thruster setup!