It doesn't cover the entire toilet seat. It starts at the front of the toilet, and doesn't go all the way to the back. The result is that there is no support in the back. My daughter is 3 yrs, 4 months, and this seat is much too weak for her. Any movement she makes causes the potty seat to sink in the back. I'm afraid that if we use it, it will soon break and she'll fall in. She definitely can't sit back, or even sit straight up because it sinks so much