This is my 4th or 5th pair of CDM Ballast's.. I've lost count and many sunglasses at that!  The reason I keep going back to the CDM Ballast are the quality and feel.  I've never broken a pair, only had them stolen (twice) and lost the other 2 pairs.  As long as Costa is making the ballast I'll keep on buying them for everyday use.  They're great for mowing the lawn, cruising the lake on a pontoon, or even driving.  I've even found they cut down the glare from oncoming (drivers using brights) headlights and strobes from buses on my morning commute down one-lane roads in the morning dark.