The 3ST numbered in it's own clients, the most important companies in the Telecommunication areas such as:
  • TELECOM ITALIA
  • ITALTEL
  • ENEL
  • T.I.M. - TELECOM ITALIA MOBILE
  • ALCATEL
  • WIND
  • OMNITEL
  • ERICSSON
  • SIEMENS
  • RAI

The operating companies in charge of different customers, is normally made in the Sardinian Region, nevertheless, the 3ST is always available for the installation end assembling in the main-land.
The company itself' started the iter for the UNI EN' ISO 9000. The most important partners, for the value of the supply and the sinergical collaboration for the satisfaction of it's clients are:
- CALZAVARA S.p.a. - UDINE A CERTIFING COMPANY with UNI EN ISO 9000.
Specialized supplers in Poles and passive repeaters, privileged partners of support in planning and constructing Telecommunication Support Building.
- CLAMPCO SISTEM S.r.l. - Romas d'Isonzo (GO) - Certificated Company UNI EN ISO 9001. supplier of antennas, accessories for installation of radio-communication plants, aircraft warning light systems and auxiliary plants.
- OMNISHELTER S.r.l. - Arluno (MI)
Specialized in Shelter and cabinet supply for storage of electrical and electronic equipments.