Gimlet

"No shield, no problem!"

- Sumiharu Inukai, after his captain breaks the Idras' Shield with Gimlet.

Gimlet is a Border Trigger, and the composite bullet created through the combination of two Asteroids.

Appearance
Unlike Asteroid bullets, which appear as lines, Gimlet projectiles are vaguely ellipsoidal in shape, with a short, luminous tail and thin circles surrounding them. When used by a Shooter, their size depends on their number and the trion capacity of the user.

Overview
Since composite bullets were created by Kōhei Izumi, Gimlet could not have existed until three years prior to Yūma's enlistment in Border.

Large-Scale Invasion Arc
It was first seen used by Izumi to intercept a Rabbit from attacking Osamu and Chika.

B-rank Rank Battles Arc
During Galopoula's Invasion, Ninomiya uses it to destroy Idras' combined shield.

Abilities
As the combination of two Asteroid cubes, a Gimlet bullet is made out of twice the trion of an Asteroid one, which grants it enhanced penetration abilities. It is used to breach sturdy Shields or firm armor as well as to inflict damage. Thanks to their extraordinarily high trion levels, Izumi and Ninomiya can create Gimlet bullets so powerful they can break the armor of Rabbit, which is capable of deflecting an Ibis blast, and the combined shield of four Idras, previously shown to be able to withstand multiple shots from Sniper Triggers.

As a composite bullet, Gimlet is very powerful, but, when used by Shooters, it requires times and focus to be created, rendering the user vulnerable in the process, so it cannot be used uniformly. The time necessary to merge the two trion cubes ranges from one minute for inexperienced users to a mere two seconds for masters.

Users
See also: Gimlet Users

The only known users of this composite bullet are two top-tier Shooters, Kōhei Izumi and Masataka Ninomiya.

Trivia

 * Like many other Gunner Triggers, Gimlet may be named after a missile: the SA-16 Gimlet, an early version of the 9K38 Igla. Alternatively, it may be derived from the homonymous rocket.
 * A gimlet is also a drilling tool.