My Kong Slyde was part of a Doble Longe kit sold by Expé. The rope was simply 9 mm. accessory cord with a knot tied at each end. Although it is easily adjusted with the knot provided, it does not appear to me that it is suitable for use as a dynamic cow's tail in this configuration. It is a better choice for a normal cow's tail that will never be shock loaded than the Zyper is, mainly because it weight much less and uses a smaller, more convenient size rope.
Expé
did not rig the Slyde in the way that Kong recommends. The Kong
Climbing 2000 catalog shows three drawings of the Slyde on page
128. The middle drawing is misdrawn so that it shows an impossible
rigging. The other two drawings show the Slyde rigged as shown
to the right. This rigging is for a single cow's tail only. It
cannot be used for a double cow's-tail since it will slip in one
direction; however, it is almost secure in the other direction
(if the proper cord is used, approximately 9 mm.) and is easier
to adjust than the rigging shown above.