just a design, to make a working model would have cost many thousands and the uk company i spoke to in depth about it wanted over a grand per model manufactruered!
which mad ein china would cost say 90£
i no nothing of your capabilities with NV gear, so please dont get offended by this, a design without a working model is nothing more than a picture/idea etc
putting something together thats actually usable is a whole different ball game. a working model wouldn't cost a great deal other than parts and labour if you have access to the right equipment. try and get something botched together and see if it works, if you need a hand with anything drop me a PM.