Here at Smoky Mountain Hunting Supply we have experimented for the past several Bear seasons to try and maximize the range on our DC 50, T5, TT10, TT15 & this past season we put them on the T5X and TT15X collars. We have got the length and wire guage figured out that we feel maximizes the range of the Garmin collars at least here in the Smoky Mountains. These antennas out perform the stock antennas by a good margin. If extending the range of your Garmin collars is a need you feel is important you should try one of these antennas.  We don't promise any color as we have made these out of several colors but we can try and get the color you desire if we have these made up at that time in that color.