http://www.paulstravelpictures.com/Fagor-Splendid-Pressure-Cooker-Review/Fagor-Splendid-Pressure-Cooker-Review-009.JPG
Bottom of a Fagor pressure cooker. Looks pretty much like the pics of the cookers used as bombs.
Still from Fox bomb photo with Gas Electric Inox clearly visible.
http://www.mediaite.com/tv/fox-broadcasts-crime-scene-photos-of-exploded-pressure-cooker-bomb-from-boston-marathon/