Questions as to what I wear in the winter months training our MIL and LE…..this Crye Precision chest rig fits great over my down jacket and/or shell. If you truly train year around one of these is necessary when temps drop to the low 20s and teens and you’re in it for 12 hours. I use this setup in all extreme cold weather classes except low vis and CQB.” – Defoor Proformance Shooting