This is a tow hitch receiver for a Lexus GX460. It just happens to be an almost bolt-on  option for Ryobi 48V mowers. It utilizes the bolts that hold in the battery tray, so I'm not sure if it would work in the RM300e since it doesn't have a battery tray.

You'll need to drill some holes in the frame tube behind the battery and add a couple M8 or 5/16 bolts to complete the installation. For more pictures and details, see this Reddit post.

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Thatch is the built up of dead grass and roots under your actively growing grass. When there's too much thatch, it prevents new grass from  growing, resulting in a thinner lawn. Excess thatch can make your lawn appear yellow, particularly during the colder months. The tines on this thing will pull up the thatch as you tow it.

You'll want some weight on it to keep it from bouncing around. A 16 x 8 x 4 inch cinder block attached with a bungee cord to each side will do the trick. The blocks are about $2 at Home Depot or Lowe's.

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Lawn sweepers are a fast way to pick up debris from your yard. They'll pick up sticks, leaves, pine cones, walnuts, and thatch as easily as driving over them. They have long brushes connected through gears to the wheels, so when you drive, the brush spins, throwing whatever is in front of it into the basket. Then back it up onto your dump pile, pull the rope to lift the basket up to dump the contents. You don't even need to get off the mower. Just dump it slowly or everything ends up on top of the sweeper.

It's a huge time saver. The main downside is these things are a bit bulky to store. However, the basket comes off easily and will fold down by removing the rear vertical supports.

Find it on Amazon or Vevor. Use code VEVORAFF for 5% at Vevor.

When you're not mowing, you can think of your mower as a large mobile battery. An inverter lets you leverage that battery for emergencies, events, or working in remote sections of your property. Most small inverters on the market are for 12 Volt systems. While there are a few for 48V, the  Zetawale GXTK-48V-2500 stands out for quality and performance at a good price.  It's rated for 2500 Watts continuous and 5000 Watts peak. 2500W is roughly the equivalent of a 20A breaker. Fully loaded, you'd get about 2 hours of runtime from a 100Ah battery.

Find it on Amazon. Sometimes they run out of stock. You can message the seller to see when they will be available.