They were '59/'60'/'61 hard back buckets and were in Cadillacs, Buicks, Olds, and Pontiacs. There is a very nice pair on Facebook right now for $3500 but they don't have the mounting brackets which differed by make. I have a pair of restored shells and stainless I will sell I'd have to think about what I'd want for them. There was an ad in '61 showing a set of them in a '61 Impala convertible although they were never offered in Chevys. As someone said '58 Bonnevilles also had them but the bottom shells were slightly different than the '59-'61 shells.