The present invention relates to a coffin with a lower side and an upper side. Said coffin comprises a structure and an inner lid, where the structure includes a first frame located on the lower side of the coffin, a second frame located on the upper side of the coffin, a plurality of ribs connected to the first frame, protruding towards the upper side, and connecting the second frame with said first frame, and a covering surface connected to the ribs. In turn, the inner lid has an arcuate shape and is arranged on an inner side of the second frame, where the ends of the inner lid arcuate shape lay on the ribs of the structure. Moreover, in some embodiments of the invention the coffin comprises at least one retractable handle arranged on the cover surface. Said handle can comprise a handgrip, a lanyard connected to the handgrip and to the first frame; and an elastic element connected to the cover surface and coupled to the lanyard. The elastic element is set up to exert an elastic force on the lanyard that allows for the handgrip to be drawn towards the cover surface.

Embodiments for streamlined training are provided. One embodiment of a rental casket insert includes a base for receiving a deceased onto an interior surface that includes a lower panel, a first base end panel, a second base end panel, a first base side panel, and a second base side panel, where the base is configured is defined by a base length, a base width, and a base height. The rental casket insert may also include a lid for engaging with the interior surface of the base that includes an upper panel, a first lid end panel, a second lid end pane, a first lid side panel and a second lid side panel, where the lid is defined by a lid length, a lid width, and a lid height, where the lid height is greater than the base height, and where the lid includes at least one detachable portion, wherein the at least one detachable portion is configured as a perforated section for removal to allow coupling of the lid with the base when a deceased is disposed in the base against the interior surface.