Noting that the Promark system is a fair bit cheaper to purchase, can anyone tell me if they have any experience with the Promark in cold weather - typically working in -20 C, sometimes -30 C weather. Our Locus system works fine on the D cells getting about 20 to 30 hours out of a set, some days are colder than others. I want to add some more receivers but don't want something that won't last the day in colder weather. Thanks.

My solution for the ProMark2 is a sandwich bag with spare batteries in my pocket. If that sounds like a bad idea to you go with more Locus. You will not get 20 to 30 hours on a set of batteries in the ProMark2.

You are probably right, I did see where someone had adapted an external power supply. Thanks