Just about all of the kits are made in China.
The ones that come in a heat sealed packet with a brand on it are good, they come direct from the factories that supply the engine makers or carb assemblers.
The ones that come is a zip lock bag with nothing but a product code on them is a 50:50 change of the parts being correct and another 50:50 chance the parts being in spec.
I can buy rebuild kits from China for 5¢ a piece in quantities of 100 or more.
The square area of good quality gasket material is more than 5¢
I can buy bulk mixed gaskets & diaphragms by the kg for next to nothing ( about 10,000 ) in a kg, but there is a good reason why bulk mixed parts are so cheap.
Metering chamber gaskets come in 4 thickness and we are talking .005" differences, but the wrong one will either cause the engine to run rich or lean
Then there are diaphrams, dozens of them look identical but again the sheeting is different thicknesses and in this case we are talking of 0.00005" increments.
Then there is the pin in the metering diaphragm, they are again different lengths and the lengths are again only a thou or two different.
Over here there are a lot of people with no idea making lots of money selling 5¢ kits for $5.00 to cheapskates who are firm believers in rip off consparices & cartells .
After they have bought 3 of them, then a complete carb that "fits" and the tool still does not work they come to me or toss it in the bin & go buy another tool.
The Echo branded kit will be more expensive than the Walbro branded kit purely because of higher logistical expenses of getting it to your door.
Again, getting the RIGHT Walbro kit is the problem.
My wholesaler lists around 2000 kits