97% cotton; 3% spandex. This is a medium weight shirt. Good as new.
No defects.
Was this a volunteer Marshal's shirt? I don't know. The Skipjack in the back very large, so probably so.

HILTON HEAD ISLAND, S.C. – October 2, 2018 – The Heritage Classic Foundation is pleased to announce that Southern Tide, the premier coastal lifestyle and apparel brand, has signed a multi-year agreement as the “Official Style” sponsor of the RBC Heritage Presented by Boeing. This is a notable partnership for RBC Heritage, as this is the first time the Heritage Classic Foundation has partnered with a lifestyle apparel brand.

Measurements in inches:
Length 32
Chest 50
Shoulder 22

Refer to last pix, A, D, & E.