Kratos - 10m Length Helixon Retractable Wire Rope Fall Arrest Block - Vertical Use 10m10m Length Helixon Retractable 4. 5mm Wire Rope Fall Arrest Block with Polymer Casing Vertical Use Only Casing made up of high impact strength Polymer. Smaller and lighter design. x2 Swivel rotations. Usable in explosive atmospheres. This Kratos Helixon Fall Arrest Block is approved for Vertical use only. For models approved for Vertical and Horizontal Use see the Helixon S models. Complete with swivel snap hook at attachment end with built in fall