This professional handheld fruit wine refractometer is designed for winemakers to measure sugar content, judge fermentation progress and final alcohol potential of fruit wine, cider and berry brews. It adopts high-transmittance optical prism with built-in ATC automatic temperature compensation, effectively eliminating reading deviations caused by temperature changes and providing precise instant results without batteries. The lightweight ergonomic body with anti-slip rubber grip allows easy single-hand operation for vineyards, home brewing workshops and beverage factories. Just drip a tiny amount of fruit mash or wine liquid on the prism to read clear scale data in seconds. Matching sturdy plastic storage box is included to protect the tester from scratches, bumps and dust during outdoor sampling and long-term storage, extending its service life greatly. This portable detector helps brewers adjust raw material ratios and control fermentation cycles accurately. Durable, easy to clean and carry, it is an essential quality control tool for commercial wineries and DIY fruit wine