Is there a patent: none.
Specifications: coaster style 1 (bamboo), coaster style 2 (lotus root), coaster style 3 (orchid), coaster style 4 (plum blossom), coaster style 5 (lotus flower), coaster style 6 (pattern), coaster style 7 (heart shape), coaster style 8 (square), coaster style 9 (hexagon), coaster style
Material: bamboo
Specifications: coaster style 1 (bamboo), coaster style 2 (lotus root), coaster style 3 (orchid), coaster style 4 (plum blossom), coaster style 5 (lotus flower), coaster style 6 (pattern), coaster style 7 (heart shape), coaster style 8 (square), coaster style 9 (hexagon), coaster style
Material: bamboo