about 180 degrees! Sorry, I had to. A half round is generally made of plastic these days and covers the top half of the chainstay. So when you look at a tube cross section > O < a half round would be like a letter > C < tipped 90 degrees to the right, and on top of the tube like a hat. One of those on each chainstay is supposed to protect your chainstay from being crushed.
Kickstands that I used to buy decades ago used to have a plate with the half rounds already in it. But with bikes having different spacings now, I get why they just supply a flat plate. ******** includes half rounds with their double kickstands. Wish I woulda had the forethought to have added a plate when I had my couplers added. duh!