Professional mechanics who value precision and control over the charging process will appreciate the Schumacher Electric DSR ProSeries DSR139 Manual Timer-Controlled Wheeled Battery Charger and Engine Starter. Unlike fully automatic models, the DSR139 gives users complete authority over the charging process with its 135-minute manual timer and rate selector switch, allowing for custom control over every charging session. Perfect for demanding shop environments, this charger features a 225 cranking amp (12-volt) engine start, powerful enough to jump start cars, trucks, SUVs, and large engines with ease. The DSR139 also offers three versatile boost modes—50-amp 12-volt, 25-amp 6-volt, and 25-amp 12-volt—to quickly recharge deeply discharged batteries, while the 10-amp charge mode ensures a steady recharge for regular maintenance. This charger is compatible with a wide range of battery types, including 6-volt and 12-volt standard, AGM, gel, and deep-cycle batteries. Built for the pros, the DSR139 is designed to withstand heavy use with its rugged metal casing and solid-core wheels. The retractable handle allows for convenient storage, and the 6-gauge output cables remain flexible even in freezing temperatures. Plus, the color-coded clamps ensure a secure connection on both top- and side-mounted battery posts. The Schumacher Electric DSR139 is the perfect manual wheeled charger for mechanics who want power, reliability, and full control over their battery charging and engine starting needs.