code/__DEFINES/inventory.dm

WEIGHT_CLASS_TINY	Usually items smaller then a human hand, (e.g. playing cards, lighter, scalpel, coins/holochips)
WEIGHT_CLASS_SMALL	Pockets can hold small and tiny items, (e.g. flashlight, multitool, grenades, GPS device)
WEIGHT_CLASS_NORMAL	Standard backpacks can carry tiny, small & normal items, (e.g. fire extinguisher, stun baton, gas mask, metal sheets)
WEIGHT_CLASS_BULKY	Items that can be weilded or equipped but not stored in an inventory, (e.g. defibrillator, backpack, space suits)
WEIGHT_CLASS_HUGE	Usually represents objects that require two hands to operate, (e.g. shotgun, two-handed melee weapons)
WEIGHT_CLASS_GIGANTIC	Essentially means it cannot be picked up or placed in an inventory, (e.g. mech parts, safe)

Define Details

Items that can be weilded or equipped but not stored in an inventory, (e.g. defibrillator, backpack, space suits)

Essentially means it cannot be picked up or placed in an inventory, (e.g. mech parts, safe)

Usually represents objects that require two hands to operate, (e.g. shotgun, two-handed melee weapons)

Standard backpacks can carry tiny, small & normal items, (e.g. fire extinguisher, stun baton, gas mask, metal sheets)

Pockets can hold small and tiny items, (e.g. flashlight, multitool, grenades, GPS device)

Usually items smaller then a human hand, (e.g. playing cards, lighter, scalpel, coins/holochips)