Etherstack's (ASX:ESK) Australian subsidiary won its first international contract to supply its NATO Narrowband Waveform technology to an unnamed defense wireless equipment manufacturer, according to a Tuesday filing with the Australian bourse.

The current contract value is under the company's market materiality threshold and is for initial technical evaluation purposes, per the filing.

The evaluation may or may not result in a material future contract award, Etherstack said.

Its shares fell nearly 4% in recent Tuesday trade.