With all of the security features of a high security portal, the Circlelock Combi is a retrofit option for companies looking to upgrade their security level, while utilizing the additional protection of an existing fire / smoke / airtightrated door. The interlocking half portal attaches to an existing swing door, saving on both space and renovation costs and transforming an ordinary door into a high security entrance, capable of protecting the most sensitive areas from unauthorized entry and piggybacking.