There are a wide variety of Police Earpieces on the market, whether you need an Overt or Covert Earpiece, listen only or with Push To Talk (PTT) and Microphone, whether you want in ear or headset, D Shape, G Shape or Acoustic and choice is to be honest 100% personal preference! What I will do today is run over the basic pro's and con's of each type of police earpiece and their normal uses but ultimately you have to try a few different types and find what works for you.
With covert ear pieces you have a couple of options a wireless in ear receiver and hidden mic that runs to a minimum of £200 and probably more like £500 or the more common acoustic earpiece with clear coiled tube which will set you back anywhere between £12 and £20. The clear tube runs out of the back of the wearers shirt collar and loops over the top of the ear and into the ear canal. There are two options then for fitting the tube into the ear canal, either the standard "Mushroom Tip" which blocks the whole ear canal of the "Gel Earpiece Insert" that fits into the ear well to hold it in place and then a smaller tube runs into the ear canal allowing both clear transmission of comms without the earpiece completely cutting off ambient local sounds. Acoustic Covert earpieces can have a 3 wire PTT and Mic allowing the mic to be lapel mounted or hidden in a sleeve or listen only.
G Shape police ear pieces fit like an inverted G made of black plastic or rubber, hooked over the top of the ear with the earpiece speaker coming down to the opening of the ear canal (some ear pieces have it swivel mounted others don't). General consensus is that the G shape earpiece is the most comfortable for the most users.
D Shape Police Earpieces (surprisingly enough) are black plastic or rubber D Shapes with the curve hooking round the back of the ear and the straight part running down the centre of the ear with the speaker mounted in the middle to align with the ear opening. These do not fit as close to the ear as a G Shape earpiece and people with bigger ears may tend to find they flap about like Dumbo when running!!
Both D and G Shape earpieces are available in PTT and Mic or listen only and will normally set you back anywhere between £10 and £20.
The most common police radio earpieces are for Motorola MTH800 and CP040 Series, Sepura SRP 2000 series and a few models of Kenwood.