Here's a great spring collarless overshirt option from our British friends at SEH Kelly. I particularly enjoy how this would come in handy in lieu of a suit jacket for in case you have a spring wedding you need to attend. They've perfectly mixed a lightweight yet sturdy cotton-drill and 11-wale beige-grey corduroy, to give it some interesting texture as well as a nice neutral base for your daily kit. As with all of their garments that use buttons, they only employ real horn, both on the placket and the patch pockets. Behind the lower front pockets (which appears to be just one) there are actually two– one on top of the other. The slant opening leads to what they call a "slouch" pocket behind the main pocket. It's also unlined which keeps any bulky feeling in warmer weather non-existent.