Featherweights have a very distinct look to them and some very identifiable features. Key features include black suitcase type rectangular box case, machine weighs 11 pounds, flip up extension bed, only sews straight stitch, thin flat bobbins, scroll or striated (striped) face plate and distinctive decals. They do not say Featherweight on the machine and only some models (after 1956) have 221 below the Singer badge. If it comes with the original instruction booklet, model 221 should be on the front cover.