There have been several models of Mecha Sonic in various games of the series. Although universally known as
The duel of the skies

Mecha Sonic In Sonic and knuckles

Metal sonic

Mecha Sonic Comic Verison

Mecha Sonic in Japanese media, many of these models were not initially named in English-language media. The model from Sonic the Hedgehog 2 for the Master System was referred to as the Silver Sonic in the Master System and English Game Gear manuals, and this name has occasionally been used for other models in the series.

Mecha Sonic first was in:

Sonic & Knuckles