Undershirts.... which ones and why.

Undershirts. Definitely a conversation that is not going to come up often is what undershirt you wear.
The absolute worst thing you can wear is 100% cotton. A cotton blend isn't much better. This includes the heavily marketed Under Armour charged cotton. Cotton is not breathable nor does it wick moisture. Once it's wet it gets heavy and sticks to you skin. For law enforcement there really is nothing better than a moisture wicking shirt made out of a synthetic such as polyester. The few times I have been asked what kind of undershirt I wear, it was always followed with," I don't know what you do for a living but I'm the Police I can't afford under armour." I always answered "I can attest we don't make a lot of money but you can afford it if you shop sales and by one piece at a time." Since then I have worn multiple high end/ high price and Burkes specials. The best overall out of any of the brands is hands down Russel 360 Dry-Fit from Walmart at roughly $14 a shirt. They are a heavy weighted synthetic. They wick moisture and keep you cool just as good as Under Amour and Nike. One issue I've had with some Under Armour in the past is that over time they peel where the vest straps go over your shoulders. It doesn't happen on all of them but it does on some. I've yet to have a Russel do that. Simply put for the price you can't beat them. If you don't believe me try it yourself I think you will be surprised.