Table: headphones_specs
Columns: headphone_model
headphone_class
sensitivity_db
impedance_ohms
driver_matched_db
construction
earpads
termination
succeeded_by

Question: Name the number of headphone class for sr100
SQL: SELECT COUNT("headphone_class") FROM headphones_specs WHERE "headphone_model" = 'SR100'

Question: Name what succeeded by for foam
SQL: SELECT "succeeded_by" FROM headphones_specs WHERE "earpads" = 'Foam'

Question: Name the headphone model for succeeded by sr125
SQL: SELECT "headphone_model" FROM headphones_specs WHERE "succeeded_by" = 'SR125'

Question: Name the driver matched db for joseph grado signature
SQL: SELECT "driver_matched_db" FROM headphones_specs WHERE "headphone_class" = 'Joseph Grado Signature'