This is an officially licensed Pink Floyd product.
This shirt features a promo for Pink Floyd's "Dark Side Of The Moon - A Piece For Assorted Lunatics" 1972 tour. On this tour, Pink Floyd played the entire "Dark Side" album before it was released.
Sheer t-shirts are made of a soft material and are slimmer fitting than your average t-shirt. Sheer t-shirts are generally made of a cotton/polyester blend, but may also be 100% cotton. The shirts are not see-through nor is there any loss of quality.