Modifications

Each weapon can be customized with certain modifications (mods). These mods come in the following categories:
 * Optic (Large and Small)
 * Muzzle (Large and Small)
 * Underbarrel (Large and Small)
 * Magazine
 * Skin
 * Dye

Modification uses
The current known uses of modifications
 * Optics: enabling weapon to zoom in when a button is pressed increase accuracy.
 * Muzzle: enabling weapon to have a silencer for reduced threat, a loud vent brake for increased threat, or other muzzles if a different attribute is preferred.
 * Underbarrel: enabling weapon to have attachments to stabilize it, or to use a laser to increase accuracy.
 * Magazine: enabling weapon to have a magazine that extends ammo or makes reloading faster.

Description
Each modification consists of a level, and a Rarity, as shown in the image on the right. Increasing the level or the rarity of the modification improves the number of bonuses and their percentage increases. Muzzle, Optic, and Underbarrel modifications also have a size restriction applied as well. Any weapon with a large modification slot can take small or large modifications of the same type, but weapons with small modification slots can only take small modifications of that type.

Restrictions
A modification can be applied to any weapon as long as the following apply: For example, a level 7 character has a level 6 Vector Submachine Gun. The Vector has the following slots: Magazine, Muzzle (Small), Optic (Large), Skin, and Underbarrel (Small). This character can apply any level 7 modifications or lower to this weapon. The Vector has every available slot, however, for the Muzzle and Underbarrel slots only modifications of those types that have a small size can be used. In the case of the Optic, with its large size, any Optic modification Large or Small can be fitted.
 * 1) The characters level meets or exceeds the level of the modification,
 * 2) The weapon has a slot of the corresponding modification type available, and,
 * 3) The weapon can take a modification of the given size in the case of Optics, Muzzle, and Underbarrels.

Skin and Magazine modification slots have no size restrictions, so the corresponding modifications can be applied to any weapon that has an available Skin or Magazine slot.

Modification Sources
Modifications can be bought or sold from merchants, crafted using the crafting system, or be given as rewards from missions or encounters.

Trivia

 * In Survival, Elite enemies will use flashlight Modifications instead of usual Laser pointers.
 * This mod is not available for use by the player in the main game, and isn't used anywhere outside Survival.