External Hex Implants. Southern’s range of Externally Hexed Implants are available in diameters 3.25mm, 4.0mm, 5.0mm and 6.0mm, Diameters of 8.0mm and 9.0mm are also available in External Hex MAX Implants. Implant lengths vary from 6mm to 20mm and all implants are surface roughened with Southern’s extensively proven and well dokumented enhanced surface. The External Hex range has an impressive prosthetic selection to accommodate a vast range of prosthetic requirements that may arise. This, together with our ideal to offer compatibility with other major brands, gives the patient more options of treatment, showing that Southern Implants offerts more choices.