UNDA-WUNDATYPEWRITER PADS, ADDING MACHINE PADS, DUPLICATOR MACHINE PADS AND RELATED OFFICE EQUIPMENT PADS Classification InformationInformation not providedMark DetailsSerial NumberNo 72129755

Gerren HotRod TypewriterCoChris Aldrich this is the mat I use. It's $15 and it's soaked up 5 years of everything I do and it still looks like the day I bought it.

You might not want to get too hung up on sound deadening material. Anything is better than nothing and stick on felt works just fine. Most of the noise from a typewriter comes from the paper being slapped between the platen. A new platen will give you more quiet sessions. Any felt added will keep out any high pitch resonant echos but it's not going to do a whole lot for the overall volume you will experience. A good typing mat like wool, and a new platen are by far the two optimal solutions for noise. Felt can be a bonus but unless it's a complete tin can rattle trap, the difference between 1mm and 3mm felt probably isnt going to rock your world.