The Shield Top should be the first thing you put on (after your heart-rate strap) when getting ready for a ride.
Base layers are ideal for all conditions: they transfer sweat away from your skin to keep you cool when it's hot, and they keep you warm and insulated when it's cool. Can you ride with a base layer year-round? Yes, you can, and you should.
Tight Fit - The Shield Top is a first-layer garment that provides extra comfort under a jersey.