Bolas

Bolas are the the second gadget that Catwoman receives. They are three spherical, metallic pellets tied together with ropes that could be thrown at enemies to stun them. They were Catwoman's equivalent to Batarangs.

Arkham City Incident
After Catwoman decided to break into Hugo Strange's Vault, she knew that she needed her weapons to get the task done. Catwoman headed over to her apartment to get her Caltrops and Bolas. Like Batman's Batarangs, she seemed to be able to carry an arbitrarily large amount of weaponry.

Arkham Knight Incident
The Bolas worked identically as they did in Arkham City. They could also be used to stop a charging thug and KO him instantly (same as Batarang charger).

Trivia

 * Like other ally gadgets, Bolas are real life weapons.