A guide for firearms which extends along an axis (X-X), mechanically and electrically engageable by an accessory device, wherein the guide comprises: - a coupling body which extends in length along the axis (X-X), comprising: i) two rows of teeth (21, 22), placed on opposite sides of the coupling body along the axis (X-X), mechanically engageable by the accessory device; ii) an interaction surface, located between the two rows of teeth (21, 22), comprising a plurality of interaction modules, wherein each module comprises a pair of main holes (251a, 251b) and a secondary hole; - an electronic group comprising: m) a plurality of electric contacts comprising: a plurality of main pairs of electrical contacts (301a, 301b) respectively housed in the pairs of main holes (251a, 251b); a plurality of pairs of secondary electrical contacts (302a, 302b), wherein each pair (302a, 302b) is housed in the respective secondary hole; n) an electronic board which extends in length along the axis (X-X) comprising a primary system engageable by the main electrical contacts (301a, 301b) and a secondary system engageable by the secondary electrical contacts (302a, 302b); - a switch group, housed in the coupling body, operationally connected to the electrical contacts (301a, 301b, 302a, 302b) to move them between an inactive position where they are detached from the respective system (311, 312) and an active position in which, upon the action of the accessory device,they are in contact with the respective system (311, 312). - a coupling body which extends in length along the axis (X-X), comprising: i) two rows of teeth (21, 22), placed on opposite sides of the coupling body along the axis (X-X), mechanically engageable by the accessory device; ii) an interaction surface, located between the two rows of teeth (21, 22), comprising a plurality of interaction modules, wherein each module comprises a pair of main holes (251a, 251b) and a secondary hole; i) two rows of teeth (21, 22), placed on opposite sides of the coupling body along the axis (X-X), mechanically engageable by the accessory device; ii) an interaction surface, located between the two rows of teeth (21, 22), comprising a plurality of interaction modules, wherein each module comprises a pair of main holes (251a, 251b) and a secondary hole; - an electronic group comprising: m) a plurality of electric contacts comprising: a plurality of main pairs of electrical contacts (301a, 301b) respectively housed in the pairs of main holes (251a, 251b); a plurality of pairs of secondary electrical contacts (302a, 302b), wherein each pair (302a, 302b) is housed in the respective secondary hole; n) an electronic board which extends in length along the axis (X-X) comprising a primary system engageable by the main electrical contacts (301a, 301b) and a secondary system engageable by the secondary electrical contacts (302a, 302b); m) a plurality of electric contacts comprising: a plurality of main pairs of electrical contacts (301a, 301b) respectively housed in the pairs of main holes (251a, 251b); a plurality of pairs of secondary electrical contacts (302a, 302b), wherein each pair (302a, 302b) is housed in the respective secondary hole; a plurality of main pairs of electrical contacts (301a, 301b) respectively housed in the pairs of main holes (251a, 251b); a plurality of pairs of secondary electrical contacts (302a, 302b), wherein each pair (302a, 302b) is housed in the respective secondary hole; n) an electronic board which extends in length along the axis (X-X) comprising a primary system engageable by the main electrical contacts (301a, 301b) and a secondary system engageable by the secondary electrical contacts (302a, 302b); - a switch group, housed in the coupling body, operationally connected to the electrical contacts (301a, 301b, 302a, 302b) to move them between an inactive position where they are detached from the respective system (311, 312) and an active position in which, upon the action of the accessory device,they are in contact with the respective system (311, 312).