This set of parts came about when a customer required an easier way of loading their filament on the BCN3D Sigma. Although there is a set of parts on Thingiverse to do just that, they do require a bit of work and take a long time to print. With everything we design for the Sigma, we strive to ensure any upgrade is reversible. A bit like car phone kits in leased vehicles, we find clever ways to fit bits in and secure them with the minimum of intrusion.
A customer has even modified the spool hangers to take 2.3kg spool!
There are two versions of the Sigma chassis and we will need to know which one of these you have. The easiest way to identify this is to measure the distance shown in the screen cap below.