Geo Fence Receivers too BIG & too HEAVY?

Geo Dog Fence Receivers i.e. Halo Brand, SpotOn Brand, Invisible Fence Brand, Pet Safe Brand, etc weigh about 8oz which is 1/2 lb and are too big, cumbersome, uncomfortable, do not hold up long around the necks of rough & tumble dogs. Geo Dog Fence Receivers are not 100% guaranteed waterproof and seem too heavy for dog 40lbs or less. [...]