Sit Tight Polypropylene Toilet Seats The sit tight hinge offers peace of mind that your seat will be easy to fit, durable and maintain a clean finish. No more movement! About this item NO MORE MOVEMENT grip pad technology ADJUSTABLE HINGES fit all standard toilets (suits toilet pans with hinge centres between 110 and 190mm) ANTI-BACTERIAL treated surface protects against harmful bacteria, odours and staining BOTTOM FIX installation All fixings included.