The Atlas V heavy (HLV) was a proposed variant of the Atlas V that would have used 3 common boosters. In 2015 ULA confirmed that it will not make an Atlas V heavy
...Plus configuration.
This model is 1/100 in scale. The pins connecting the boosters are 9/64in, these can either be printed with the included files or made from wooden dowels.
This model was made with ABS on a Zortrax M200. Using other printers/materials may affect the tolerances.