A quick learner from Wilmington says:
July 27, 2015
You don't list a S160p but you sent one when i ordered 4 s160, 2 for each side. If you need the P to attach more than one why did you send just 1 s160-p? Can I attach the two s160's on one side?
Tom from SWISCO responded:
July 29, 2015
Thanks for submitting the pictures. The spring you showed is, in fact, our S160-6. The key stamp here is "#6.5," which indicates how much weight it can support. The "P" is just a manufacturing mark. It does not denote anything in particular.