The group I ride have used the Collett 900 comunicators for about 4 years. They work good for quick commands like: slow down, tight turn, need gas, upcoming sleds, etc. They are not great if you want to carry on a conversation. Some people come in loud and clear and others come in somewhat garbled. It has to do the mic position and any gear they may be wearing that may muffle their speech. Overall we really do like them and have come to rely on them for trail warning and to keep track of our group. The leader no longer needs to stop and verify everyone is still in the group, the leader just calls back and we all check in.
I also use the colletts 900. Few years old now, The older one's had a problem with frezing the mic after a long day. I sent mine in (bought them used) and only paid the shipping. Mic were updated and then made sure they were in tune. I do like them, and miss them when you don't have them.Agreed, not like your talking on the phone, more like a cell phone driving on the highway. But you can hear and fairly clear. Other nice feature is when your out and Mr Groomer is also out.Most club subscribe to the GWB, groomer warning beacon. Trust me you'll know somethings around.The new one's have a cell phone jack, guess so you don't have to take off your lid. Older one;s have a mono jack, pipe in a walkman or whatever.
I use two FRS radios with a mic and earbud in the helmet, Works great. Use an external PTT to key and made it big to use with mitts. Cost me maybe $10 to make I think. Excepting cost of radios of course.
You get wind noise but can be controlled with foam around the mic element. Some velcro holds it into the helmet. 
I have the HJC FRS communicators. They work great on a lake, but in the trails I only get about 500-800 feet of reception. If its hilly or has alot of trees, the reception is like less than a 1/2 mile. I use the voice activated mic and it works pretty good. If you have a loud sled and get on the throttle, it will activate. Never used my PTT button yet. They are ok, but dont expect 1 to 2 miles for reception. Not with the power the units out there are putting out. Bought mine on ebay, brand new in the box for $125.00 a piece. Beets $200.00.
With any communications equipment, some things remain a constant. Height of the antenna is the single most important factor for VHF/UHF (FRS frequencies), in which the luxery of having a big antenna on a sled is asking for problems. The major factor for us sled riders is called isolation from electromagnetic noise. In other words the engine in the sled causes interferiance with the radio. If you here the engine when you wind the sled you need to move the radio further from the engine. Any radio properly preped will work, however, batteries are a diffrent case.
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