Most coils for various detectors work the same, although they may not interchangeable, the products listed below are the coils i am using on my T2se or other metal detectors in my possession, but please bear in mind, the T2 only operates with DD Coils and not concentric or multi-frequency coil…

Shown below is a good “coil comparison diagram”

Shown below is the difference between the size, and how it affects the frequencies of the different coils, and how much it affects the depth & width of the search pattern, bearing in mind the size of the coils, but if you assume the two larger ones are 8″ with a 5″ coil on the far right…

Although the DD coil is not so deep, it is only slightly less than the concentric coil, however where the concentric coil falls down, is on various different mineralised soils, because you never run on the optimum ground, however, the DD coil is more stable and less chatty without losing any real noticeable depth, when the sensitivity is set high, whereas you would have to lower the sensitivity when detecting with a concentric coil, as you can see from the diagram the nail is not within the intended target area of a DD coil whereas it is with the concentric coil, so with the DD coil a signal has less interference, in contaminated soil, you can use the DD coil to great effect, the concentric coil being slightly more sensitive is great for clean ground or parks where the trash signals are the same as wanted targets…

Does size matter, with coils…

In my opinion “yes” it does…

Here’s why my opinion is “Yes”… The size of any metal detector coil influences the detection depth and sensitivity of the metal detector itself because a metal detector coil works by emitting electromagnetic waves...

The smaller the coil the fewer electromagnetic waves are created… When these fields of electromagnetic waves, come into contact with a metal object, this metal object then produces its own eddy current within the metal object, which then generates its own electromagnetic waves, it is these waves from the metal objects that are registered by the metal detector…

the factory coil for the T2 whether it’s for the classic green or black-se, it will work very well in all soils…

Although a small coil is not as deep as a large coil, it does have a more concentrated electromagnetic field, making them more sensitive to small objects & tiny fragments, making these metal objects more easily detected…
When you chose to use a smaller coil, you gain a lightweight and “easily” maneuverable coil, as these smaller coils can fit in small or tight places, & very easily fit in between the rows of stubble, that gets left behind when the crop has been harvested… For many, depth is everything, but although depth will not change too much, the size & shape of small coils are changing, & like the one, i have my eyes on at the moment, which is a ten by five, these narrow coils i hope will allow me to cover more ground, yet have the benefit of a smaller coil …

Shown below on the left, is the Nel coil for the T2, this was not my favorite, no matter how hard you try the manual ground balancing was difficult, as was pinpointing, pinpoint or ground balancing although difficult, were just two issues, but i never had faith in the coil, it never seemed to be sharp and i felt i was just missing items…

Shown below right is the standard 8″ DD coil for the five-pin Tesoro range of metal detectors, not large by today’s standard 11″ plus DD coils, but this coil can still hold its own…