In March and April last year, the aim of the whole product was to be simple/the simple thing with simple cost was to make a good sample of the round tube in the middle. The thickness of the upper shell and the lower shell in six sizes was adjusted and the angle of the upper shell was adjusted to the minimum as much as possible. In the past year, the 3D proofing on the left side of the bottom figure in the bottom figure of the last year was yellow and could not be