Quiet Close Toilet Seats can be installed on one-piece toilets that utilize special anchor kits due to the design of the toilet.
The Quiet Close Toilet Seats will however not use the wingnuts that are included with the seat to attach the bolts from the underside. Instead, simply tighten the bolts from the top into the anchors to attach the seat.
Additional Resources:
Video: Quiet Close with Grip Tight Toilet Seats
Video: Remove and Install Anchor Kit 84999 on One Piece Toilets
