Hi Jeffrey,

Thank you for contacting Mearto with your appraisal inquiry.
As you might expect, there have been few auctions of Herm Prell violin bows on their own, without either the violin or other bows but Skinner Auctions in Boston got $2,000 for one in 2011 against an estimate of $300-500 (https://www.liveauctioneers.com/item/10155615_121-silver-mounted-violin-bow-herman-prell-c-1920). That bow was lacking its horsehair and had silver mounts (sometimes silver can tarnish and acquire a yellowish patina that might look like gold so it's important to check for marks on the metal to confirm one way or the other).
Based on the photos and information provided, and subject to examination, this is:

An antique Herm W. Press silver or gold mounted violin bow
early 20th Century
with horsehair strings, intact winding, leather thumper, frog inlaid with mother-of-pearl eye, and metal ferrule and screw.
29 1/4 inches long
CONDITION: appears to be in very good condition
PROVENANCE: inherited
$1,500-2,500*
*represents a fair-market value for auction purposes; retail or asking price may vary.

Please let us know if you have additional items to appraise, and thank you again for using Mearto.