Genuine Pentax wind-up lever seat assembly for the S1, S2a, S3, and the Repronar. This part may fit the SV however I do not have that camera to verify fit. Brand new part. This seat is sold with the return spring wound-up on the seat with a keeper and test wind lever to hold the assembly together during shipping and installation. Part sold as pictured. Made by Pentax Japan. IMPORTANT. DO NOT REMOVE THE SCREWS HOLDING THE WIND LEVER TO THE SEAT UNTIL YOU INSTALL THE UNIT ON THE CAMERA. THE SPRING IS WOUND UP AND WILL UNWIND WITH SOME FORCE AND POSSIBLY CUT YOUR FINGERS. You need to look carefully at the way the winding seat fits on your camera.  My advice is to practice removing and installing the old part on your camera first. Some instructions in the service manual address the removal of this part from the camera, here.