Incubators feature a lift-out shaker platform which accommodates a range of flask clamps, test tube racks, and a microtiter plate clamp. Four load-bearing positions are incorporated for optimal weight distribution. Counter-balanced weighting system (SI6 and SI6R) is adjustable to accommodate off-center loads, varying capacities and stroke lengths. Shaking executions range from gentle to vigorous, and from 30-400 rpm. Alarms are provided for temperature, rpm and time. Over-temperature protection is provided by an independent safety thermostat, which is adjustable. A safety switch halts shaker rotation when the door is open.