Shaped to "feel" like a regular seat, it won't pinch or collapse like other cheaper "thin plastic" models (the extra solid plastic is why we cost a little more for shipping). This snap-on toilet seat fits any standard 3,4,5 Gallon Bucket. Has the shape and sturdiness of a regular seat, doesn't buckle or "shift", locks onto the bucket solidly (see pictures) - nobody wants surprises using a portable loo. Standard buckets of various sizes at your hardware store have click on lids, these seats use that edge. Great for camping, boating, RV, and emergency safety. Put one in the car for rapid evac.