NS Novelties Sinful Black Wrist Cuffs. Sinful has been the name in affordable playful kink black. Now, Sinful just made sexy a little bit sexier! NS Novelties is excited to introduce Sinful: Black. Everyone has favorite collection is now available in a stunning midnight black finish while continuing to deliver the quality you expect. Black, nickel free anodized hardware, aesthetically striking embossed vinyl, and lined in soft yet durable liquid-play friendly neoprene. Product materials Vinyl, Neoprene.