Horizontal Double Piston Extender (2-Wide) Flush with the wall 1.12 [v.2] - Screenshots - Show Your Creation - Minecraft Forum - Minecraft Forum
Downward Double Piston Extender, it works but I don't understand why. Any explanation? - Redstone Discussion and Mechanisms - Minecraft: Java Edition - Minecraft Forum - Minecraft Forum
Fast and simple double piston extender for moving Mobs/Players! : r/redstone
Is This The Smallest Double Piston Extender ?
Simple double piston extender : r/Minecraft
Ridiculous double extenders in all directions: Observer blocks | Minecraft - YouTube