Hmf filter foam

[Kelvin0727]

Does anyone know where to buy porter foam for HMF filter beside Swiss tropical? I saw this comply (link below) selling speaker foam which is also 30ppi spec and a lot cheaper then Swiss tropical but I'm not sure if this is the right one to use. Can anyone shed some lights?

http://www.foambymail.com/SFF-/speaker-filter-foam-30-ppi.html