The Lindapter type HB Hollo Bolt with hexagonal head is the Original Expansion Bolt for Structural Steel. Suitable for hollow sections, tubes and where access is only available from one side. The Hollo-Bolt (hexagonal head, HDG) is approved by ICC-ES to resist seismic loads and wind loads in all seismic design categories (A to F). For corrosion protection, the Hollo-Bolt comes with additional JS500 protection as standard or hot dip galvanised. Sizes M16 and M20 have a patented High Clamping Force (HCF) mechanism for optimised clamping force. Speedy installation with standard tools. This CE approved blind fixing was awarded the Design Council's Millennium Product status for innovation in the year 2000.