This glassfinder works very well if there is green grass, while if there is yellow or light color leavels fall down every where, it won't change the enviroment a lot then make it a big difference comparing with white golf ball.
The golf ball finder glasses only works when part of the ball can be seen through the gap of grass leaves, if the ball was blocked throughly by the rough grasses, please be noted the finder won't work like an ultrasonic machine - it won't help you see through the grass leaves.
This range finder in theory filters the color of surrounding green area to yellowish-brown, which in result increases the color contrast between the balls and the environment, and ultimately guides golfers in searching their lost golf balls.