Zip-Kick

The Zip-Kick is a grapple-type weapon used by Robin to hook onto enemies and it propelled him over to the enemy. It was the Robin equal to the Batclaw and could be used as a not only a weapon, but a mode of transportation, and acted like a mix between the Grapnel Gun and the Batclaw.

Initiation Incident
Bruce Wayne utilized a Zip-Kick, on account of his lighter armor, during Initiation by Master Kirigi.

After Arkham City Incident
When Batman was captured by a vengeful Harley Quinn after the Joker's death, Robin used his Zip-Kick to get past a few obstacles and took down Harley's Henchmen who got in his way.

After Arkham Knight Incident
Red Hood used the gadget as he made his way to Black Mask. It worked identically to Robin's version, most likely due to Jason Todd having similar experience about its use.

Trivia

 * If Robin used the Zip-Kick on a henchmen and he fell into the water, his skeleton disappeared if Detective Mode was used.
 * Dick Grayson, as Robin, used his Zip-Kick in Batman: Arkham Origins Multiplayer.
 * The device used by Bruce Wayne was yet to be identified as Zip-Kick, and was called "Grapple Gun" instead.
 * Unlike Robin and Jason, Bruce Wayne could not use the gadget from a vantage point. However, his variant could be used to pull vent covers from a distance, something the two Robins couldn't do.
 * If the player is too close, they pull and punch the thug instead.
 * If there are enemies in front of the person you zip kick, you will ram through them.
 * The Zip-Kick is the only gadget usable with all three Robins (Dick in Origins, Jason in Knight, and Tim in City and Knight). As the "Grapple Gun", it's also usable as Bruce Wayne, making it one of the two gadgets used by every member of the main Bat Family Trio, alongside the Grappling Hook.