"US" Finneboks har en tversoverbolt i bakkant og et vertikalt skruehull foran. Finfin løsning for opptil ca 32cm finnelengder. USBox finner kan lett bygges om til SlotBox (ut med pin & kapp frontfestet).
In 1964 Bill Bahne started Fins Unlimited to address the needs of surfers desiring a removable and adjustable fin system. In 1968 Bahne applied for a US Patent for the “Adjustable Surfboard Fin Holder” or the fin box as it came to be known. The patent was granted in February 1971. Bahne’s fin box design was readily accepted as the industry standard. Much of the success was attributed to the fact that the box could accept a wide variety of laminated fiberglass fins.