450cc refers to an implant volume of 450 cubic centimetres. It is a full-to-large choice, but the result it gives is highly individual.
Roughly who it suits
As a very general guide, 450cc is often discussed by patients seeking a full-to-large increase. On a petite frame the same 450cc will read as a larger jump in apparent size than on a taller, broader frame. Your starting tissue and chest width change the outcome significantly.
Why width and profile still matter
Two 450cc implants can look very different depending on whether the volume is delivered as a wide, flatter implant or a narrow, projecting one. Surgeons fit the implant to your base width first, then use profile to dial in projection.
Getting it right
Trying sizers in a bra and reviewing before-and-after photos of patients with similar measurements is far more reliable than fixating on a cc number. See choosing implant size.