It wasn’t until 1959 when Sylvania was merged with General Telephone to create the recognized Sylvania GTE (General Telephone & Electronics Corporation). This was the beginning of a truly massive change for the company and its international expansion.
In early the 1960s, the Costa Rican company Multilux, that focused on the distribution of electrical products, decided to bring the franchise of GTE Sylvania and this lead to the establishment of the luminaries plant in 1964 in Pavas, San José, Costa Rica. This plant began making bottles, consoles, appliances, lights, chips for cars, breakers, starters and fixtures. In the decade of the 70s, incandescent bulbs and fluorescent tubes were incorporated, and the plant gradually began to specialise in lighting solutions setting aside their other markets.
In the early 90s, GTE has to make substantial investments in the emerging field of mobile telecommunications, which was beginning to compete with their core business of traditional telephone systems. Sylvania was sold to fund new investment. Sylvania’s division for Europe, Asia and Latin America led to the formation of SLI Holdings International LLC.