From the website:
Field a full 10-man Khenetai Occult Blade Cabal with this bundle of 10 plastic Mark IV Space Marines and two sets of resin upgrade components.
The resin upgrade sets are designed to allow you to upgrade ten plastic Mark IV Space Marines to the status of a Khenetai Occult Blade Cabal. It contains ten torsos, ten right arms and ten left arms (each wielding force swords, meaning two of these curved blades for each model) and ten heads. These parts replace their equivalents from your Mark IV Space Marines, turning them into this Elite choice for a Thousand Sons Legion army list.
The Sekhmet, also known widely as the Scarab Occult outside their Legion, were the elite of the First Fellowship of the Thousand Sons, and when called upon to do so, served as Magnus’ personal bodyguard. Clad in Terminator armour, each of them was a high initiate of the Prosperine Mysteries who had sublimated their abilities and emotions into the highest levels of spiritual control, and were able to shun injuries by mere strength of unified will that even to a Space Marine would have proved mortal.