US Patent 9200499 Dual wiper plug system

A dual wiper plug system having a first wiper including a first body having a first bore therethrough, and at least one wiper fin disposed around the body, a second wiper disposed axially above the first wiper, the second wiper including a second body having a second bore therethrough and a first shoulder formed on the inner surface of the second body, and at least one wiper fin disposed around the body, and a first collet ring coupled to the first wiper and including at least one collet finger extending axially upward, and a collet head disposed on an upper end of the collet finger and configured to engage the first shoulder of the second body.