Housing to housing spring for all FTA and DCM models. 
Note Below:

-FTA models require 1ea. per clamping mechanim, i.e. 1ea. for a 1-FTA model, 2ea. for a 2-FTA model.   -DCM models require 2ea. per clamping mechanism, i.e. 2ea, for a 1-DCM model, 4ea. for a 2-DCM model.