Call of Chernobyl is a free-play sandbox mod for S.T.A.L.K.E.R. : Call of Pripyat created by TeamEPIC. It features 32 explorable maps, reworked level design and level fixes, new original level, Trucks Cemetery, Full AI and A-Life overhaul, engine and script enhancements, Repeatable task system which bases itself on A-Life events, Customizable weather environments for every map as well as surges and psi-storms from AF3, Character creation which includes name, portrait and faction selection; Several optional modes such as Ironman mode, story mode and zombie survival mode, New achievements, rankings and reputation system, PDA leaderboard and enhanced PDA statistics, Companion system with keyboard issued commands, many optional side-features and community-made addons . Call of Chernobyl was player's choice Mod of the Year 9th place in 2015 and 1st place in 2016!
Setting slot_persistent to false in system.ltx will enable a new feature for that slot.
Now it is possible to equip knives, grenades and binoculars without a visible slot for them. Equipped items will be highlighted on the inventory screen. You can equip and unequip at will. There are a few uses like item degradation or perhaps binocular progress where the beginner one doesn't zoom, the next one has zoom and the third one has zoom and enemy recognition or new custom items that share that slot.