A piston pushes the block in front of it when powered. The sticky variant also pulls a block back on retraction, making it the workhorse of doors and flying machines.
Bedrock Edition · Block dictionary
Piston — spec
Push limit
Up to 12 blocks
Delay
2 game ticks before responding
Sticky variant
Pulls the front block back on retraction
Immovable
Cannot push obsidian, bedrock, or extended pistons
