beyond the upper face of its respective medial horizontal support member 52 54 56 to permit such cylindrical portion 88 to be capped upon its upper end at this point it should be noted that the upper ends of the other lower vertically extending support members 26 terminate within the medial horizontal support member 52 54 56 as shown in fig7 cylindrical first portion 88 includes in the nature of sleeve 84 a vertically extending through opening that receives upper vertically extending support member 27 in a slippery sliding fashion pincher 86 further has a threaded second portion 90 extending upwardly and integrally from cylindrical first portion 88 pincher 86 further includes a slotted tapered third portion 92 extending upwardly and integrally from threaded second portion 90 third portion 92 includes a set of four vertically extending slots 94 disposed at ninety degrees relative to each other pincher 86 further includes a pinching collar 96 rotatably mounted on vertically extending support member 27 pinching collar 96 has inner threads that engaged threaded second portion 90 and further includes a tapered inner surface that circumferentially engages tapered slotted portion 92 to reduce the width of slots 94 and thus the diameter of portion 92 such that portion 92 circumferentially grabs and frictionally holds member 27 relative to member 26 the tapered features of pinching collar 96 and third portion 92 permit a fixing of members 26 and 27 with each other to a relatively greater or lesser degree in an incremental manner such that for example the height of the upper barrier section 18 can be temporarily set with a medium degree of drag produced by slotted.