first came out "Sony Celebrates Walkman 20th Anniversary" sold 186 cassette playing Walkman devices first came out first came out « Sony Celebrates Walkman 20th Anniversary » "Sony Celebrates Walkman 20th Anniversary" «Sony Celebrates Walkman 20th Anniversary» history of the Walkman a bit off Sony's history of the Walkman selling close to 200 million units selling close to 200 million units Sony's history of the Walkman sold 186 cassette playing Walkman devices "Sony Celebrates Walkman 20th Anniversary" sold 186 cassette playing Walkman devices history of the Walkman publicly stated Sony's history of the Walkman Sony Walkman TPS-L2 selling close to 200 million units first came out history of the Walkman