Today's electronics have a protective coating on the screens. Harsh chemicals including sunscreen will damage it. These protectors also offer mechnical protection; rings, hooks, etc. I'm not pushing the vendor just the concept. I have them on all of mine including I phone.
Nice i got one on my iPhone as well, didnt know they made these for the Garmin. Will be picking one up. Thanks
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78' / 20SF / Merc XRi Black Max 150