This is an officially licensed Saturday Night Live product.
This shirt says "Open The Box" from the SNL D*ck In A Box sketch.
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.