Fin kan kai (ko kai kawai) wani nau'i ne na mahaɗin lantarki.Hoton fil na namiji ya ƙunshi layuka ɗaya ko fiye na fitilun ƙarfe waɗanda aka ƙera su zuwa gindin filastik, sau da yawa 2.54 mm (0.1 in) baya, kodayake ana samun su a tazara da yawa.Maza fil masu kai suna da tsada saboda sauƙin su.Abokan takwarorinsu na mata wani lokaci ana kiransu da masu kai mata soket, kodayake akwai bambancin suna na masu haɗin maza da mata.A tarihi, wasu lokuta ana kiran masu kai “Berg connectors”, amma kamfanoni da yawa ne ke kera kanun labarai.