The following constants are inside InvItem.

PISTOLS_ITEM
PISTOLS_AMMO_ITEM
UZI_ITEM
UZI_AMMO_ITEM
SHOTGUN_ITEM
SHOTGUN_AMMO1_ITEM
SHOTGUN_AMMO2_ITEM
REVOLVER_ITEM
REVOLVER_AMMO_ITEM
CROSSBOW_ITEM
CROSSBOW_AMMO1_ITEM
CROSSBOW_AMMO2_ITEM
CROSSBOW_AMMO3_ITEM
HK_ITEM
HK_AMMO_ITEM
GRENADE_GUN_ITEM
GRENADE_AMMO1_ITEM
GRENADE_AMMO2_ITEM
GRENADE_AMMO3_ITEM
HARPOON_ITEM
HARPOON_AMMO_ITEM
ROCKET_LAUNCHER_ITEM
ROCKET_LAUNCHER_AMMO_ITEM
LASERSIGHT_ITEM
SILENCER_ITEM
BIGMEDI_ITEM
SMALLMEDI_ITEM
BINOCULARS_ITEM
FLARE_INV_ITEM
TIMEX_ITEM
PC_LOAD_INV_ITEM
PC_LOAD_SAVE_ITEM
BURNING_TORCH_ITEM
CROWBAR_ITEM
DIARY_ITEM
COMPASS_ITEM
CLOCKWORK_BEETLE
CLOCKWORK_BEETLE_COMBO1
CLOCKWORK_BEETLE_COMBO2
WATERSKIN1_EMPTY
WATERSKIN1_1
WATERSKIN1_2
WATERSKIN1_3
WATERSKIN2_EMPTY
WATERSKIN2_1
WATERSKIN2_2
WATERSKIN2_3
WATERSKIN2_4
WATERSKIN2_5
OPEN_DIARY_ITEM
GOLDROSE_ITEM
PUZZLE_ITEM1
PUZZLE_ITEM2
PUZZLE_ITEM3
PUZZLE_ITEM4
PUZZLE_ITEM5
PUZZLE_ITEM6
PUZZLE_ITEM7
PUZZLE_ITEM8
PUZZLE_ITEM9
PUZZLE_ITEM10
PUZZLE_ITEM11
PUZZLE_ITEM12
PUZZLE_ITEM13
PUZZLE_ITEM14
PUZZLE_ITEM15
PUZZLE_ITEM16
PUZZLE_ITEM1_COMBO1
PUZZLE_ITEM1_COMBO2
PUZZLE_ITEM2_COMBO1
PUZZLE_ITEM2_COMBO2
PUZZLE_ITEM3_COMBO1
PUZZLE_ITEM3_COMBO2
PUZZLE_ITEM4_COMBO1
PUZZLE_ITEM4_COMBO2
PUZZLE_ITEM5_COMBO1
PUZZLE_ITEM5_COMBO2
PUZZLE_ITEM6_COMBO1
PUZZLE_ITEM6_COMBO2
PUZZLE_ITEM7_COMBO1
PUZZLE_ITEM7_COMBO2
PUZZLE_ITEM8_COMBO1
PUZZLE_ITEM8_COMBO2
PUZZLE_ITEM9_COMBO1
PUZZLE_ITEM9_COMBO2
PUZZLE_ITEM10_COMBO1
PUZZLE_ITEM10_COMBO2
PUZZLE_ITEM11_COMBO1
PUZZLE_ITEM11_COMBO2
PUZZLE_ITEM12_COMBO1
PUZZLE_ITEM12_COMBO2
PUZZLE_ITEM13_COMBO1
PUZZLE_ITEM13_COMBO2
PUZZLE_ITEM14_COMBO1
PUZZLE_ITEM14_COMBO2
PUZZLE_ITEM15_COMBO1
PUZZLE_ITEM15_COMBO2
PUZZLE_ITEM16_COMBO1
PUZZLE_ITEM16_COMBO2
KEY_ITEM1
KEY_ITEM2
KEY_ITEM3
KEY_ITEM4
KEY_ITEM5
KEY_ITEM6
KEY_ITEM7
KEY_ITEM8
KEY_ITEM9
KEY_ITEM10
KEY_ITEM11
KEY_ITEM12
KEY_ITEM13
KEY_ITEM14
KEY_ITEM15
KEY_ITEM16
KEY_ITEM1_COMBO1
KEY_ITEM1_COMBO2
KEY_ITEM2_COMBO1
KEY_ITEM2_COMBO2
KEY_ITEM3_COMBO1
KEY_ITEM3_COMBO2
KEY_ITEM4_COMBO1
KEY_ITEM4_COMBO2
KEY_ITEM5_COMBO1
KEY_ITEM5_COMBO2
KEY_ITEM6_COMBO1
KEY_ITEM6_COMBO2
KEY_ITEM7_COMBO1
KEY_ITEM7_COMBO2
KEY_ITEM8_COMBO1
KEY_ITEM8_COMBO2
KEY_ITEM9_COMBO1
KEY_ITEM9_COMBO2
KEY_ITEM10_COMBO1
KEY_ITEM10_COMBO2
KEY_ITEM11_COMBO1
KEY_ITEM11_COMBO2
KEY_ITEM12_COMBO1
KEY_ITEM12_COMBO2
KEY_ITEM13_COMBO1
KEY_ITEM13_COMBO2
KEY_ITEM14_COMBO1
KEY_ITEM14_COMBO2
KEY_ITEM15_COMBO1
KEY_ITEM15_COMBO2
KEY_ITEM16_COMBO1
KEY_ITEM16_COMBO2
PICKUP_ITEM1
PICKUP_ITEM2
PICKUP_ITEM3
PICKUP_ITEM4
PICKUP_ITEM5
PICKUP_ITEM6
PICKUP_ITEM7
PICKUP_ITEM8
PICKUP_ITEM9
PICKUP_ITEM10
PICKUP_ITEM11
PICKUP_ITEM12
PICKUP_ITEM13
PICKUP_ITEM14
PICKUP_ITEM15
PICKUP_ITEM16
PICKUP_ITEM1_COMBO1
PICKUP_ITEM1_COMBO2
PICKUP_ITEM2_COMBO1
PICKUP_ITEM2_COMBO2
PICKUP_ITEM3_COMBO1
PICKUP_ITEM3_COMBO2
PICKUP_ITEM4_COMBO1
PICKUP_ITEM4_COMBO2
PICKUP_ITEM5_COMBO1
PICKUP_ITEM5_COMBO2
PICKUP_ITEM6_COMBO1
PICKUP_ITEM6_COMBO2
PICKUP_ITEM7_COMBO1
PICKUP_ITEM7_COMBO2
PICKUP_ITEM8_COMBO1
PICKUP_ITEM8_COMBO2
PICKUP_ITEM9_COMBO1
PICKUP_ITEM9_COMBO2
PICKUP_ITEM10_COMBO1
PICKUP_ITEM10_COMBO2
PICKUP_ITEM11_COMBO1
PICKUP_ITEM11_COMBO2
PICKUP_ITEM12_COMBO1
PICKUP_ITEM12_COMBO2
PICKUP_ITEM13_COMBO1
PICKUP_ITEM13_COMBO2
PICKUP_ITEM14_COMBO1
PICKUP_ITEM14_COMBO2
PICKUP_ITEM15_COMBO1
PICKUP_ITEM15_COMBO2
PICKUP_ITEM16_COMBO1
PICKUP_ITEM16_COMBO2
EXAMINE_ITEM1
EXAMINE_ITEM2
EXAMINE_ITEM3
EXAMINE_ITEM4
EXAMINE_ITEM5
EXAMINE_ITEM6
EXAMINE_ITEM7
EXAMINE_ITEM8
EXAMINE_ITEM1_COMBO1
EXAMINE_ITEM1_COMBO2
EXAMINE_ITEM2_COMBO1
EXAMINE_ITEM2_COMBO2
EXAMINE_ITEM3_COMBO1
EXAMINE_ITEM3_COMBO2
EXAMINE_ITEM4_COMBO1
EXAMINE_ITEM4_COMBO2
EXAMINE_ITEM5_COMBO1
EXAMINE_ITEM5_COMBO2
EXAMINE_ITEM6_COMBO1
EXAMINE_ITEM6_COMBO2
EXAMINE_ITEM7_COMBO1
EXAMINE_ITEM7_COMBO2
EXAMINE_ITEM8_COMBO1
EXAMINE_ITEM8_COMBO2