Uppercases slot defines.

code/game/objects/items/devices/flashlight.dm

@@ -8,7 +8,7 @@
 	righthand_file = 'icons/mob/inhands/misc/devices_righthand.dmi'
 	w_class = WEIGHT_CLASS_SMALL
 	flags_1 = CONDUCT_1
-	slot_flags = SLOT_BELT
+	slot_flags = ITEM_SLOT_BELT
 	materials = list(MAT_METAL=50, MAT_GLASS=20)
 	actions_types = list(/datum/action/item_action/toggle_light)
 	var/on = FALSE
@@ -348,7 +348,7 @@
 	icon_state = "slime"
 	item_state = "slime"
 	w_class = WEIGHT_CLASS_SMALL
-	slot_flags = SLOT_BELT
+	slot_flags = ITEM_SLOT_BELT
 	materials = list()
 	brightness_on = 6 //luminosity when on