item_generic

A universal item. Plays back a custom sound and activates a target when picked up. Can be used for creating items in a map editor.

Spawnflag

SF_ONLY_IF_IN_SUIT

1 (allow pickup only if the player is wearing the suit)

model	Model of the item.
noise	Sound or sentence that is played back on pickup.
netname	Name of the icon that shows up on pickup, as for a regular item (see the description in hud.txt).

The item itself does not modify the player's inventory in any way. You can use it to activate a target in the map so that the pickup is associated with a specific event. This lets you update the player with keys, access cards and so on.
The player can also carry the item, as they can other items.