[Milsurplus] Seeking PRT4 info

[Toscano]

 I have located a source of clean, operational PRT4s and was considering
 purchasing some. The gentleman claims to have tested them and labeled them
 according to condition found and frequencies in them.
 Questions:
 1) What's a reasonable price to pay (USD) for one? It looks like they are
 being offered at US$30 each, including instructions on expedient battery
 construction using commercial 9V cells.
 2) What kind/size of crystals are in these radios? Any known sources for
 cheap replacements (looking to match my unit's frequency of 39.90 MHz).
 3) How do these perform versus other military radios? Having known the
PRC77
 and 25 I am very familiar with their range, audio quality, etc. How does
the
 PRT4 stack up?

 Thanks to all in advance.

 David C. Toscano
 KB1ILS