PDA
From WikiRaider
The PDA Lara carries in Tomb Raider Legend takes over most functions of the Inventory. Lara can not only check out her gear there, but she can also store and read messages and mission details. Descriptions of the gear she carries are displayed, as well as the layout of Croft Manor. Lara also uses the PDA like a diary, recording her thoughts of a particular mission.
The PDA is waterproof and can even accompany Lara on her long journeys through water.
from the official Site
While Lara's headset keeps her in contact with her support team, her PDA is her field workspace. It stores and organizes notes on short term goals as well as useful data on gear, weapons, and progress. Its versatility is matches only by its sturdy construction - enough to withstand the abuse one might expect from accompanying Lara to the most dangerous places on Earth - and it's waterproof, too.
Underworld
Lara carries it in Tomb Raider Underworld: A revolutionary new tool that emits a sonar ping to create a 3D image of Lara's surroundings, perfect for uncovering hidden items and locations.