Foam. 10.5″ seating area width. The Stubs is short, hence the name, and it has a basic no-nonsense tough as nails presence. Like all LePera seats, well designed, made to last and look good even after time has passed. Comes with the standard high quality foam filling and is packed with the nostalgic Café Performance touch. Note: There will be a gap of 1 1/2″ between seat and tank on all XL models with 3.3 gallon tanks.