Propeller Tachometer Roberson & Company This is called a TACH CHECK. Handheld propeller tachometer made by Roberson & Company. Not electronic, etc. just a handheld propeller tachometer with instructions on back on how to set indicator on TACH CHEK to desired R.P.M. and tighten nut, etc. until the propeller appears stationary it is turning at the same R.P.M. as indicated on this tachometer. Personally, I know nothing about airplaines but listed this just in case a pilot would love having this as a collectible. Age unknown. I you need more photos, just ask.
Circa: Unk
Condition: Like New
Manufacturer: Roberson & Company