What kind of collar did Robert Deniro wear in analyze this?

Robert De Niro wears a black turtleneck sweater in "Analyze This." It's a classic and iconic look for the character, Paul Vitti, and it's not technically a collar, but rather a style of shirt.

The turtleneck sweater is a significant part of his character's image, as it suggests both his power and his vulnerability. The high neckline can be seen as a symbol of his protectiveness and control, while the softness of the knit fabric hints at his inner anxieties and fragility.