Just got one of the GTC 340 copies of a comet/salsbury 340. I took it apart to see how it compares with the originals and it is a very close copy. Looks like they came over on a slow boat as it was a bit corroded and had moly spray all over it on the sheaths, so I cleaned up everything and started to get ready to assemble. The screws holding the axles for the weighted rollers are cheap so I am waiting on some new ones but otherwise looks just like my real ones and it is rated to 8500. Rollers weigh 51 grams (steel) and there are no 51 gram ones in the original salsbury charts just 55 gram steel ones are the closest to it. . I did not measure spring wire diameter but will go back out and measure.