CREATE TABLE table_41550 ("Headphone Model" TEXT, "Headphone Class" TEXT, "Sensitivity  ( dB ) " TEXT, "Impedance  ( Ohms ) " FLOAT, "Driver-matched dB" TEXT, "Construction" TEXT, "Earpads" TEXT, "Termination" TEXT, "Succeeded by" TEXT)

What are the earpads of the headphone with a plastic construction, an unknown sensitivity, and was succeeded by sr325?
SELECT "Earpads" FROM table_41550 WHERE "Construction" = 'plastic' AND "Sensitivity (dB)" = 'unknown' AND "Succeeded by" = 'sr325'
SELECT "Earpads" FROM "table_41550" WHERE "Construction" = 'plastic' AND "Sensitivity (dB)" = 'unknown' AND "Succeeded by" = 'sr325'