- The HCPA-1 silicone stent is made of biocompatible silicone, medical grade, via injection process in the matrix using different densities of the same material for a set of prostheses with rigid and flexible variables; available in the following dimensions (diameter x length in mm): 9x30, 9x50, 11x30, 11x50, 13x30, 13x50, 14x30, 14x50, 16x50, 16x70, 18x50 and 18x70. Requires specific surgical (applicator) for insertion.