Hi: There's a new model of glasses, sold directly from China, very cheap. (14 to 18) and technically good. http://es.aliexpress.com/store/product/Belay-Glasses-for-Climbing-LePirate-Light-Technical-Belaying-specs-Tested-by-proffesionals/1020501_32358135034.html
Cheap Belay Glasses LePirate