illustrated in fig2 to be slid out of the bed 12 without the need to physically uncouple the end support 34 from its associated support rail 36 referring to fig3 5 7 and 10 the second cross bar assembly 28 is shown in greater detail the second cross bar assembly 28 includes a first tube 46 that fits telescopically within a second tube 48 tubes 46 and 48 form the cross bar component 37 with brief reference to fig3 a first tube 46 includes a spline 46 a that rides with a groove 48 a in the second tube 48 when the two tubes are assembled this allows rotation imparted to second rube 48 to cause a corresponding rotation of the first tube 46 the purpose for which will be described momentarily collars 47 a and 47 b are preferably formed from high strength plastic and help to prevent metal to metal contact between the two tubes 46 and 48 with further reference to fig3 and 10 a hook member 50 is coupled to one end of the first tube 46 the hook member 50 includes a jaw 52 which engages with a pin 54 of end support 40 when the cross bar assembly 28 is in a locked orientation the pin 54 is supported within a neck 56 of a camming component 57 a body portion 58 includes flanges 58 a having a plurality of wheels 60 supported for movement a section of body portion 58 fits within support rail 42 the support rail 42 has a generally u shape when viewed from one end and serves to capture the wheels 60 as well as a section of the body portion 58 within a channel formed by the support rail 42 thus the end support 40 is attached.