These are great!! In Japan, sliding doors are very common and these are used in the sliding doors.
They are from the "昭和" "showa period" . The "showa" period is from 1926-1989.
These would be fabulous as frames for your art, a small dish for teeny tiny objects etc.
They measure 6.5 x 6.5 cm.The "hole" measures 4.8 cm.