What headphones you need are all based on what model you are getting so before you make your purchase you need to make sure that you’re looking at the product and see if they need headphones and if they do, whether the product you’re buying comes with them or they need to be bought separately.
A lot of the products on this list are handheld devices that you can use to scan the floor. With these products they don’t need headphones as they will alert you to a finding another way, either by vibrating or using a display. This is a very easy to use product and a very simple one in terms of its detection system.
There are also metal detectors which make on a more traditional look which are underwater models and some of these have headphones while others don’t. The ones that don’t have headphones will work in the same way as those handheld models and work via vibrations and lights. The ones that use headphones should have them attached to the model so they’ll be no need to buy them separately.
The other type of option available is the type of detector that has a waterproof coil but can’t be fully submerged in the water. These types of device keep their control box out of the water so you wouldn’t need any special type of headphones in order to use these devices and they will never be fully in the water.