Laydown Collar Shirts
The laydown-style tuxedo shirt has become quite popular over the last few years. At one point, many would have argued that it is not as formal as a wing-tip tuxedo shirt. However, nowadays you will find men wearing these laydown style shirts at almost any formal event (though a laydown collar is definitely not appropriate with tuxedo tails).
The laydown collar tuxedo shirt is the same type of collar that you will find on an ordinary dress shirt, however, it is differentiated by the fact that a formal shirt takes studs.