Buy OSRS Cooked karambwan
The cooked karambwan is a members-only fish in Old School RuneScape. It restores 18 Hitpoints when eaten. It is tradeable and noteable, so it is easy to move and store.
Karambwans are best known for combo eating. You can eat a karambwan right after other food with no extra delay. This lets you heal a large amount of Hitpoints in a short time. Many players use this trick in boss fights and PvP. You can boost it even more by eating your main food, then a dose of Saradomin brew, then the karambwan. Karambwans also let you attack again after only two ticks, while most foods make you wait three ticks.
Karambwans have other uses too. They can be used in tick manipulation to speed up skills like barbarian fishing. They can also be used to make karambwan paste. Some players even use raw karambwans for Cooking training, since cooking one gives 190 experience at level 30 Cooking.
With a supply of cooked karambwans, you can stay alive longer in hard fights and heal faster than with normal food alone.