I am looking at a 70s Yamaha 9000 series but the seller is not sure what the shells are constructed of. Here is what he gave me. Can anyone make anything of this? Thanks.
9x13 - TT-913DA PY-5059
10x14 - TT-914DA PY-5031
16x18 - FT-918DA PY-5023
14x24 - BD-924DA PY-5012