There small, they look like R's, the have a yellow circle at the end that blink when they start finding an item.
Somewhere in erecutek city there is a house with a guy inside near a map he will ask if you like treasure hunting say yes and you get the itemfinder.
when you have got the itemfinder. Click start then click on bag and then press the right button on your +control pad. click on the itemfinder then click use. The itemfinder will detect any items around you that are berried.
Press use to use the itemfinder and if it dings you have found something. Walk in the direction you are facing then use the itemfinder again. continue until the itemfinder starts shaking wildly and press A facing the spot and you will find something.
somewhere
If you find an item with the itemfinder underwater, look for a patch of slightly lighter sand. go beside it, face it and press A. you should get the item in the sand. Hope this helped! Shinin
If you have the itemfinder app for the pokech, go by the bottommost building and use the itemfinder.
Just find the itemfinder press A and select 'use' then you're using it!
The itemfinder will point you in the direction of where hidden items are press A in that direction to find the item.
Simply press the A button in the direction the itemfinder is pointing to.
You have to use the itemfinder to look for the guy's glasses. You will find the black glasses once you find it with the itemfinder. Those glasses boosts the power of dark type moves. Although those aren't the glasses the person is looking for. So you'll get to keep them.
In Pokémon Yellow, you can obtain the Itemfinder by visiting the house in Goldenrod City, which is located north of the Pokémon Center. Inside, you'll find a man who will give you the Itemfinder after you show him that you've caught at least 30 different Pokémon. The Itemfinder helps you locate hidden items on the ground throughout the game.
Pokemon emerald