We introduce GooseFX SSL v1, a new design of decentralized exchange and liquidity provision that 1) enables simple single-sided liquidity pools, 2) enhances liquidity concentration and reduces slippage, and 3) protects LPs against impermanent loss. There are three key ingredients in our design. First, we introduce a new type of curve that concentrates liquidity around the current market price. Second, we allow prices to flexibly switch between the curve and the oracle, so that LPs are protected. Lastly, we offer favorable prices as incentives for trades that rebalance assets and liabilities. We demonstrate the advantages of our design both analytically and through simulation.