One Piece: 10 Facts Everyone Should Know About Gear Second
Can anyone achieve gears in One Piece? Like how Luffy can achieve second gear and third and whatnot, can anyone with devil fruit powers achieve this? - Quora
In What Episode Does Luffy Use Gear 2 in 'One Piece?'
Gear 2 Luffy vs DCEU Justice League. - Battles - Comic Vine