The Series 25 Spinnaker Pole Slide and stop has been designed so virtually all metal components have been replaced with high-strength fiber/polymer equivalents for maximum strength-to-weight characteristics. Polymer car body delivers low friction on aluminum tracks without inserts. An ergonomic plunger pin allows for easy one-handed adjustments Ring ID: 1-3/8" (35mm) Ring stock: 19/64" (7.5mm)