Complex sentence: The first TRIAC of this type was marketed by Thomson Semiconductors (now ST Microelectronics) under the name Alternistor, and additional models are now sold under the trademark "Snubberless".
Split into simpler sentences: The first TRIAC of this type was marketed by Thomson Semiconductors (now ST Microelectronics) under the name "Alternistor". They are now sold under the trademark "Snubberless".