Check the listing for details. Tylaska DTR20 arborist rigging ring. Condition: New. Listed at 84.00 USD. Lighter and smaller than a conventional pulley block, low friction rings have become a popular alternative for many applications where traditional blocks once ruled. In addition to being lighter and less expensive than conventional blocks, low friction rings are also less prone to failure since there are no pulleys to crack or bearings to foul. Instead of rolling on a pulley sheave, the active line merely slides on the inside smooth surface of the ring. Another line is spliced around the ring as an anchor. The Tylaska DTR20 has the same running line hole as our standard TR20 ring but has the outer diameter of the TR28 ring. The design allows for a greater bend radius of the though hole containing the active rigging line which reduces the stresses and wear on the rope fiber. The "D" in DTR stands for "double" whereas the outer groove is made twice as wide as the standard TR20 ring so as to allow for two passes of line between the ears instead of the traditional single pass of line. Such a feature allows you to rig the ring with a cow hitch or larks head meaning that it is much easier to swap out rings as necessary. Inner hole Diameter: 28mmGroove width: 44mmMean Breaking Strength: 206 KN ( 46300 lbs)Wide Outer Groove allows for cow hitch or larks head attachmentExtremely wide bend radius for active rigging line to reduce wear and stressMachined from 6061 aluminumHard Coat Anodized ·