The subject of this article is featured in the new Half-Life: Alyx; therefore, its content is subject to change as more information about it is known.
"We worried about the crate cliché a lot during development. Finally we gave up, and one of the first things you see when you start the game is a crate. We figured that this was the Old Man Murray equivalent of throwing yourself to the mercy of the court."
Originally manufactured and used by the Combine, the supply crate is used in great numbers by the Resistance to hold and deliver health, ammunition, and energy equipment. Standard wooden supply crates are generally located near a Lambda logo, while infinite ammo crates are in Combine and Resistance-controlled areas.
Supply crates visually are very different from normal wooden crates, as they are much smaller and have the word "supply" written on them, inside a yellow square.
Much like other objects, crates can be picked up and destroyed by the Gravity Gun quite easily. The crowbar will always do the trick in one hit, regardless of the difficulty setting.
The supplies in the crate depend on the player's status; for example, if the player's health is low, the supply crate will usually give the player a medkit. Conversely, if the player's health is high, and has a good amount of ammo, the crates are more likely to give common supplies like 9mm pistol ammo or SMG ammo.
There are few supply crates that always contain the same items. Such examples are the ones placed close to the Crossbow usually contain crossbow bolts ammo.
Supply crates are also needed for the "Lambda Locator" Orange Box Achievement in Half-Life 2 and the "Cache Checker" achievement in Episode Two, involving the finding of every supply crate cache.
The supply crate also has a variant (the "infinite ammo crate"), which contains infinite ammo. More of the size of a trunk, it is dark green, and made out of metal. They cannot be moved or destroyed and will resupply every time they are opened. RPG infinite ammo crates will often hint an important battle to come, most of the time involving one or more Combine Gunships or Striders.
Some texture files show that infinite ammo crates were also to provide ammo for the .357 Magnum and the crossbow. They can still be added with Hammer but will display the "ERROR" model because the crate models are missing.
Before the May 26 update The Gravity Gun was unable to destroy supply crates when punted directly, as it can only be destroyed by grabbing it and than launching it at the ground. After this update, it can be destroyed with a single hit or throw.