M15A2A Chemical detection kit pouch??

I don't know where else to ask about this, if anyone can suggest a more appropriate forum, please! Recently I acquired a collection of Vietnam field gear (much as I carried myself 40 yrs ago) such as Web Belt, M14 ammo pouchs, Canteen, Butt pack, poncho, entrenching tool, etc. One item I've never seen is: US Detector Kit Chemical Agent VGH.AN-M15A2A With a faded # below that. It's 5" x 4 1/2 x 2 1/2, stiff (like M14 pouch) It is just the pouch, nothing inside; in excellent cond. Anyone know what this is and is the pouch worth anything??