11 12 13 and 14 and being indicated generally by the numeral 22 as best shown in fig1 of the drawings actually the flanges 15 and 18 are merely extensions of the walls 11 and 12 for the purpose of access the front wall 11 has a door opening 26 provided therein while the wall of the rib member 18 includes a ventilating opening 27 as again clearly shown in fig1 of the drawings referring now to fig5 it will be noted that the upper portion 26a of the door opening is provided with a smooth finish on all surfaces such as the door jamb and head that in effect serves as the finished door opening for the elevator unit with the walls 26b and all remaining walls of the door opening 26 being similarly flared out to serve as a finished door jamb also included in the precast module is a push button control box 60 and an electrical duct 60a fig6 which permits ready installation of the actual controls themselves together with their associated wiring furthermore the prefinished module includes a plurality of embedded channels 70 70 on the interior of walls 13 and 14 with these channels serving to support the side rails not shown upon which the elevator runs in addition to these channels channels 71 71 are provided adjacent the opening 26 to provide support for the door header not shown another series of channels 72 72 are provided to support the door sill and finally a plurality of channels 73 73 are embedded in the walls to provide.