You unscrew the contact plate for Boro tank and there you have the 510 connector.
To make it work as a classic SBS mod you add the included 510 extend plate, basically a
finned heat sink for atomizers, and the included top part with a slanted side.
As shown in this YouTube review:
@ 6:16
https://youtu.be/TSPRlkkfH7I?t=376