Heart Holster

Heart Holster is a passive item.

Effects

All Out Of Law - If the player has Colt 1851, it fires three tight spreads of three bullets upon reloading. These projectiles can ignore tables when fired from behind them, and they can reveal secret rooms without angering the shopkeeper Bello.
Finger on the Pulse - If the player has Pulse Cannon, upon taking damage, three miniature Pulse cannons briefly spawn around the player and fire at enemies.
Quick and the Gundead - If the player has Hip Holster, shots fired by Hip Holster home in on enemies.
Despite being able to be found in and rank chests, it will always have to be bought from a store at rank price.
Like all heart container items, The Robot will receive 5 to 10 instead.
Like the other heart container items, the Heart Holster will drop alongside a key if it is found from opening an rank chest.

The pickup quote is a reference to the phrase "wear your heart on your sleeve".
The "Quick and the Gundead" synergy is a reference to 1995 western film "The Quick and the Dead".