I purchased the Upside Lockon Range Finder and have been using it for just over a year. I don't think the silicon sleeve was available when I purchased it, but I will say it is the perfect add on. Helps to reduce any type of wear and tear in case you drop it or it gets banged around. The sleeve covers over the magnet, which I was a little concerned about at first, but the LOCKON Range Finder has stayed attached to the cart in the 5 or 6 rounds that I have played since I put the sleeve on it. I love the bright neon green color, it really makes it pop!! Plus the Neon Green sleeve makes it pretty hard to miss at the end of the round when you are cleaning out your cart!! In one of the first few rounds that I played with the LOCKON Range Finder I inadvertently left it on the cart. Thankfully someone was nice enough to turn it back into the Pro Shop afterwards. With the Neon Green sleeve it now almost impossible to miss at the end of the day.