Rain bow

The RuneScape Wiki also has an article on: rsw:Rainbow Bow

Rain bow
Released							11 April 2019 (Update)
Members							Yes
Quest item							No
Properties
Tradeable							Yes
Equipable							Yes
Stackable							No
Noteable							Yes
Options							Wield
Destroy							Drop
Examine							Short but effective and very colourful.
Values
Value							500 coins
High alch							300 coins
Low alch							200 coins
Weight							1.36 kg
Grand Exchange
Exchange							305,770 coins (info)
Buy limit							18,000
Daily volume							29
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Advanced data
Item ID							23357
Twisted League							Yes

The Rain bow is a cosmetic variant of the shortbow that can be obtained as a rare reward from easy Treasure Trails.

Attack bonuses
+0		+0		+0		+0		+8
Defence bonuses
+0		+0		+0		+0		+0
Other bonuses								Slot
+0		+0		+0%		+0		List
Attack speed							Range
							7 squares

Combat styles

Combat Options	Combat Style	Attack types	Style	Experience	Boosts
	Accurate	Ranged	Accurate	Ranged and Hitpoints	Accuracy and Damage
	Rapid	Ranged	Rapid	Ranged and Hitpoints	Attack speed by 1 tick
	Longrange	Ranged	Longrange	Ranged, Defence, and Hitpoints	Attack range by 2 tiles

Item sources

For an exhaustive list of all known sources for this item, see here (include RDT).

Source	Level	Quantity	Rarity
Reward casket (easy)	N/A	1	1/1,404