Vintage Large Wooden Harmonica For Playing or Pitch Pipe Tuning Device Unmarked?

Description

Vintage Large Wooden Harmonica For Playing or Pitch Pipe Tuning Device Unmarked? Not sure exactly what this is. There is a large brass reed plate with (13) reeds sandwiched within the wooden body. I am not really a musician so please bear with me on the description. The (13) holes are blow only. It plays a standard (8) note scale going from right to left using holes #1,3,5,6,8,10,12,13. The other (5) holes #2,4,7,9,11, seem to be intermediate sharp notes on the scale. All reeds are working and sound in tune. It appears that originally each hole was identified with the specific note, but only some are still faintly readable (see photos 8 & 9). This is a solid well made piece measuring nearly 9" long x 3 5/8" wide x 1 1/8" thick. There are (2) rubber pads on the bottom and the weight of the piece is nearly 12 ounces. Light to moderate finish wear but no cracks or dents that I see. Very interesting piece. If anyone out there has any info on it please let me know. Email any questions before bidding. Thanks for looking.