What are the differences between X40, X55, X55Plus, and X63?

Model X40 X55 X55 Plus X63
Material Aluminum Alloy Plastic Aluminum Alloy Aluminum Alloy
Shape Square Square Square Round
Foldable Foldable Foldable Foldable Foldable
Lay Flat Not Supported Supported Supported Not Supported
Size 68*68*23.3mm
2.68*2.68*0.92in
68*68*30mm
2.68*2.68*1.18in
68*68*32mm
2.68*2.68*1.26in
74*74*26mm
2.91*2.91*1.02in
Weight 195g 142g 270g 196g
Color Black Black Black Black
Gray Gray Gray Gray
Silver White - Silver
Wood - - Titanium
Leather - - -
Titanium - - -
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