The market opportunity for Bitcoin L2 is undoubtedly one of the most promising parts of the Bitcoin economic system. To estimate the overall opportunity of the Bitcoin L2 market, we draw from the experience of the existing Ethereum L2 market. Currently, the total value locked (TVL) in Ethereum L2 accounts for approximately 5.62% of Ethereum's total market capitalization. When calculating the size of the Bitcoin L2 market, we reference this ratio and apply it to the estimation of Bitcoin's market capitalization.