The strange device is an item that may be used during a master clue scroll that is similar in function to an enchanted key. It is an item used in the Hot & Cold challenge of a master clue.
The strange device can be obtained by talking to Jorral in the outpost northwest of West Ardougne only when they have obtained a master clue step that directs them to Jorral. Once you have obtained the device, you won’t have to return to Jorral. There are 116 unique Hot & Cold locations.
The strange device changes temperature as the player moves about. Its temperature is based on the distance of the treasure from the player, measured in the number of steps it would take to reach the treasure, ignoring any obstacles. The warmer the key gets, the closer the player is to the treasure. Clicking “Feel Strange device” gives information on its temperature, but will deal a small amount of damage when done so.
A list of possible locations can be found here.
When you dig at the dig spot you will be attacked by three Ancient Wizards – Each wizard uses different attack styles that will poison you. Bring food, an anti-poison and combat gear before attempting to dig at a strange device location. If the area is not multi-combat, a Brassican Mage will appear instead.