As the table evidences, the only difference between a silicone implant and a silicone explant is the external skin. Silicone implants are covered with a silicone elastomer skin whereas silicone explants are covered with a Polyurethane elastomer.
This is due to the fact that the requirements regarding the mechanical strength of (externally worn) silicone explants intrinsically more demanding than in the case of an implant that is used inside the body.
PUR elastomer skins were especially developed for the purpose of protecting the silicone gel while being hypo allergenic, washable and highly resistant against normal wear.
Marketing example of silicone explants