Great Cheyenne beaded knife sheath. possibly Arapaho?

Description

Fantastic vintage Cheyenne/Arapaho beaded knife sheath.   my guess is leaning toward Cheyenne.  From estate in Wyoming.  the approx; measurements; 11" to bottom of sheath and 19 1/2" with drop. 3 3/4" wide.
there is a slight curve to the sheath from being without a knife for so long but a knife slips in easily and straightens.
wonderful piece.  I do not know the exact age. thank you for viewing. no knife.