I’ve just taken delivery of the two bases on the left, Chinese made and sold on Ebay. They are cheap and cheerful and reasonable to good value for the price. They fit the RTO router pretty well, and hold it solidly enough for routing. Out-of-the-box, they needed some minor fettling, I tapped the holes in the bases to M4x0.75 and added washers to the clamp mechanism. I think they’ll be useful for jigs and fixtures etc, and the huge advantage of them is the view of the cutter if I’m routing a groove to a line or trying to intercept another groove. For the price - recommended, but be prepared to fettle them.