UPDATE:
got a few pieces of the UHMW flexible tubing,been experimenting with them.
1) works incredibly well for industrail use, when running ropes (static rescue) over pipes or to protect ropes from hazardous liquids in confined space situations. Best if duct taped down.
2) DRT - as some mentioned..not so good......the tubing is so slippery the minimal friction INSIDE the tubing by the rope puls the tubing from the limbs. HOWEVER: Tried it inserted tightly in a rubber hose and had great results. The grippy rubber clings tot he limb and the rope passes thru. Still does'nt compare to a friction saver (ringed).
worth the effort to try it though!