45 or similar means as are commonly employed in the art referring now to fig3 and 8 main floor 18 includes an edge unit 50 having a pair of ends 52 54 and an interconnecting side edge 56 each of ends 52 54 and edge 56 has mounted thereon a camming surface or wear bar 58 which cams against the inner edge of floor 34 as explained in greater detail below wear bar 58 is preferably constructed of nylon or any suitable substitute offering a long wearing smooth sliding surface having relatively low surface friction wear bar 58 is preferably screwed bonded or otherwise secured to edge unit 50 a retractable height adjuster 60 is mounted to edge unit 50 adjacent each of ends 52 54 each adjuster 60 includes an outer tube 62 and an inner member 63 which is reciprocally disposed within tube 62 a spring 59 is mounted within tube 62 and abuts member 63 which urges member 63 outwardly away from vehicle 12 when the slide out room 30 is moved towards the retracted position a portion of the slide out room contacts adjuster 60 and compresses spring 59 thus moving adjuster 60 out of the way when the room is in the retracted position preferably tube 62 includes a horizontal guide slot 57 which is engaged by a stop member 55 on member 63 stop member 55 and guide slot 57 cooperate to guide and limit the reciprocating movement of member 63 relative to tube 62 adjuster 60 includes a housing 65 attached to the end of tube 63 and a threaded.